Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

[Q]: Context: Did you ever make a secret code? One way to make a code is to represent each letter of the alphabet by a different number. Then you can send a coded message by writing words as strings of digits. This is similar to how information is encoded using an electric current. The voltage of the current is changed rapidly and repeatedly to encode a message, called an electronic signal. There are two different types of electronic signals: analog signals and digital signals. Both are illustrated in Figure 23.20. A digital signal consists of pulses of voltage, created by repeatedly switching the current off and on. This type of signal encodes information as a string of 0s (current off) and 1s (current on). This is called a binary ("two-digit") code. DVDs, for example, encode sounds and pictures as digital signals. An analog signal consists of continuously changing voltage in a circuit. For example, microphones encode sounds as analog signals. Electronic components are the parts used in electronic devices such as computers. The components transmit and change electric current. They are made of materials called semiconductors. A semiconductor is a solid crystalusually consisting mainly of siliconthat can conduct current better than an electric insulator but not as well as an electric conductor. Very small amounts of other elements, such as boron or phosphorus, are added to the silicon so it can conduct current. A semiconductor is illustrated in Figure 23.21. There are two different types of semiconductors: n-type and p-type. An n-type semiconductor consists of silicon and an element such as phosphorus that gives the silicon crystal extra electrons. An n-type semiconductor is like the negative terminal in a chemical cell. A p-type semiconductor consists of silicon and an element such as boron that gives the silicon positively charged holes where electrons are missing. A p-type semiconductor is like the positive terminal in a chemical cell. Electronic components contain many semiconductors. Types of components include diodes, transistors, and inte- grated circuits. Each type is described in Table 23.2. Electronic Component Diode Transistor Integrated Circuit (Microchip) Description A diode consists of a p-type and an n-type semicon- ductor placed side by side. When a diode is connected by leads to a source of voltage, electrons flow from the n-type to the p-type semiconductor. This is the only direction that electrons can flow in a diode. This makes a diode useful for changing alternating current to direct current. A transistor consists of three semiconductors, either p- n-p or n-p-n. Current cant flow through a transistor unless a small amount of current is applied to the center semiconductor (through the base). Then a much larger current can flow through the transistor from end to end (from collector to emitter). This means that a transmitter can be used as a switch, with pulses of a small current turning a larger current on and off. A transistor can also be used to increase the amount of current flowing through a circuit. You can learn more about transistors and how they work at this URL: http An integrated circuitalso called a microchipis a tiny, flat piece of silicon that consists of layers of elec- tronic components such as transistors. An integrated circuit as small as a fingernail can contain millions of electronic components. Current flows extremely rapidly in an integrated circuit because it doesnt have far to travel. You can learn how microprocessors are made at this URL: Many of the devices you commonly use are electronic. Electronic devices include computers, mobile phones, TV remotes, DVD and CD players, game systems, MP3 players, and digital cameras. All of these devices use electric current to encode, analyze, or transmit information. Consider the computer as an example of an electronic device. A computer contains microchips with millions of tiny electronic components. Information is encoded as 0s and 1s and transmitted as electrical pulses. One digit (either 0 or 1) is called a bit, which stands for "binary digit." Each group of eight digits is called a byte. A gigabyte is a billion bytes that 
 Question: electronic component consisting two semiconductors
[A]: diode


[Q]: Context: Comet ISON, formally known as C/2012 S1, was a sungrazing comet discovered on 21 September 2012 by Vitali Nevski ( , Vitebsk, Belarus) and Artyom Novichonok ( , Kondopoga, Russia). 
 Question: By whom was Comet ISON discovered?
[A]: artyom novichonok


[Q]: Context: Stu Shepard (Colin Farrell) is an arrogant New York City publicist who is contemplating cheating on his wife Kelly (Radha Mitchell). He calls Pam (Katie Holmes), a young actress, from a phone booth on a side street. When a delivery man (Dell Yount) tries to deliver a free pizza to the booth, Stu rudely dismisses him. After the phone call with Pam, the phone rings and Stu answers it. The caller (voice of Kiefer Sutherland), says that Stu should have accepted the pizza as it would have "kept his strength up for what comes next". He warns Stu not to leave the booth. Stu, again dismissive, is skeptical toward the mystery caller. The caller says that he will say 'hi' to Kelly for him, then hangs up, leaving Stu visibly concerned.The unseen man calls back and reveals that he had previously setup two other dishonest individuals in a similar situation, where he gave them a chance to redeem themselves but since both refused he had to kill them. One was a pedophile, and the other was a business executive who used inside information to cash in his stock options before the company share price collapsed (and refused the caller's request to share the proceeds with regular investors who got burned on that stock). The caller tells Stu that he must tell Kelly and Pam the truth: that he is cheating. The man calls Pam, puts Stu on speakerphone, and he tells her that Stu is married and does not want anything with Pam except to sleep with her. He then tells Stu to call his wife and tell her the truth, or else he will. Angrily, Stu does so.Before he has a chance to tell Kelly the truth, Stu is distracted by three prostitutes who want to use the phone. The prostitutes become hostile due to Stu's refusal to leave the booth, and they start banging against the glass. Stu becomes agitated and finally hangs up on his wife and yells at the prostitutes to leave him alone. As the three girls leave, the man calls and warns Stu that if he hangs up again, he will shoot him. Stu does not believe him but is convinced when the man cocks his rifle. Stu gets scared, warning him that if he shoots, the cops will arrive. However, the sniper proves him to be wrong by shooting a toy robot next to the booth without anyone noticing. The caller continues to mock Stu's faith that the caller is not capable.The situation escalates further when the prostitutes and their pimp, Leon (John Enos III), approach the booth and demand that Stu leave. Terrified that he will be shot, Stu refuses. The impasse between Stu and Leon escalates to the point of Leon breaking into the booth with a bat and attacking Stu. The sniper tells Stu he can help him and Stu says "yes". Leon is shot in the back by the sniper, horrifying the prostitutes, who accuse Stu.The police arrive and Stu is instantly the suspect. He doubts that they will find any evidence to suggest his guilt to the murder, but later finds out the sniper has planted a gun in the phone booth's roof, on top of the light panel that could be used as evidence in Leon's murder. Captain Ed Ramey (Forest Whitaker) arrives tries to negotiate with Stu to exit the booth but he says he cannot get off the call and he is talking to his "psychiatrist". Multiple news vans arrive, and reporters begin filming the situation, putting pressure on the police to deal with the situation without appearing trigger-happy. The caller continues to taunt Stu by telling him to take hold of the planted gun, or he would "Blow him (Ramey) Away!" but Stu refuses, knowing the police will likely shoot him.Kelly arrives at the scene and the sniper makes Stu confess to her about his infidelity, which Stu does. The man asks Stu to choose between Pam and Kelly, threatening to kill one of them to eliminate further temptation. The unseen caller tells Stu that there are policemen right now trying 
 Question: What is Stu's profession?
[A]:
new york city publicist