TASK DEFINITION: In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D". 
PROBLEM: [header] How to calculate a light year [title] Define the light year. [step] A light year is a measure of distance equal to how far light travels in one earth year. Because distances across the universe are so large, astronomers use light years. <sep> (A) However, they can also be determined by dividing by a distance. [substeps] Some light years are used year-round. (B) For light year 2014, the main determiner is the sun. In the light year, the world is filled with light bulbs. (C) Without light years, discussing the distance between two stars would require the use of large, unruly numbers. [substeps] Another measure of distance you may come across when learning astronomy is the parsec. (D) [substeps] There are two kinds of light years: day and night. The two types of light years are known as night and day.

SOLUTION: C

PROBLEM: [header] How to become an endocrinologist [title] Obtain a bachelor's degree in a science-related major. [step] Though you could choose any major you want, it's best to study something like physiology, biology, or social science. These majors will help you build the prerequisite skills for medical school. <sep> (A) [substeps] If you are enjoying high school, they might teach you basic tests or techniques, like how to fight ethylene gas. Foreign nationals don't get their master's degree until they finish medical school. (B) [substeps] These degree levels will take some effort on your part, so keep an eye out for whatever college you want to attend. It's not always necessary to go to medical school if you're currently planning on med school. (C) [substeps] Enroll in or look for a program at an accredited medical school. Most states require endocrinology courses at high schools and universities. (D) In addition to studying science, you should also take courses in math, english, and the humanities. These courses can help prepare you for interacting with patients and writing reports.

SOLUTION: D

PROBLEM: [header] How to fade freckles [title] Use lemon juice. [step] Lemon juice works well as a bleaching agent, and just like it works to bleach your hair, you can also bleach your freckles with it. Lemon juice won't completely remove your freckles, but over time it should fade them as it bleaches your skin. <sep> (A) Apply lemon juice by squeezing the juice out of fresh lemons, and then using a cotton ball to dab it on your freckles. [substeps] Continue this process, applying lemon juice every few days for several months. (B) [substeps] Any lemon juice substitute should work fine. For example, if you want your freckles to be an obvious shade of red, use 2-3 drops of lemon juice. (C) To add extra protective effects after bleaching your freckles, add 1 cup (250 ml) of lemon juice to your shampoo and facial cleansing products. [substeps] Mix the lemon juice and water together. (D) [substeps] Dilute a cap of lemon juice with water and squeeze out as much water as possible from the bottle. Create your own lemon juice in a plastic bucket and gently spread the juice over your freckles.

SOLUTION:
A