There are circumstances in which it is not immoral to make certain threats, and there are circumstances in which it is not immoral to ask for money or some other favor. Ttherefore, there are circumstances in which it is not immoral to ask for money or a favor while making a threat. Which one of the following exhibits a flawed pattern of reasoning most similar to that in the argument above? ['The mountain roads are treacherous after it rains, and the mountain streams are full after a rain. So, if the roads in the mountains are treacherous, and the mountain streams are full, it surely has rained recently.', 'Heavy trucks are generally operated in a safe manner, but the ability to drive a truck safely can be impaired by certain prescription drugs. Ttherefore, heavy trucks cannot be operated safely while the driver is under the effect of a prescription drug.', 'It is healthful to take drug A for a headache, and it is healthful to take drug B for a headache; ttherefore, it is healthful to take drug A together with drug B for a headache.', 'It is usually easy to move a piano after you have convinced five people to help you, provided that you do not need to take it up or down stairs. Ttherefore, it is usually easy to move a piano.']