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". 

[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.
C

[header] How to choose a protein supplement [title] Choose whey protein to build muscle. [step] If you're looking for muscle-building protein, whey protein is generally your best option. Whey protein can come in the form of powder or pills and is commonly used when people are trying to build muscle via things like weight training programs. <sep> (A) By doing this, you're gaining more body fat and growing more muscle at the same time. [substeps] Whey protein can be found in half of the packaged foods. (B) Whey protein is also a low-fat protein, rich in red blood cells from bacteria. Although whey protein does not impart healthy fats to the body, whey protein helps build muscle, which you can grow and burn through exercise. (C) [substeps] Look for a whey protein powder or supplement with a high biological value. This measures how well your body can absorb the protein. (D) Whey protein occurs as a food chain, hence the slogan, " protein is fat free ". [substeps] Whey protein is complex and varies from patient to patient.
C

A man wearing a black shirt that has white words that say "plays well with self" is sitting in a home and playing on two different bongos that are different in size, design and color. the man <sep> (A) puts the carry between himself and his legs and swishes it around and creates a circular sound. (B) is playing on the same blue bongos that are written on the screen of the keyboard, and changing course and taking a two turn to continue playing. (C) continues playing as the right hand area where the bongos used to once been standing on the right hand and there are roses there to go along with them so he doesn't have to wear them anymore and fades out after being caught looking at them. (D) stops hitting the bongos and rests his left hand on the lighter colored bongo.

D