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

A male stylist talks as he smooths a woman's hair. He then demonstrates how to cut and style her hair, clipping it as he goes. when he <sep> (A) is finished, he talks some more with a full set of hair tools. (B) is done, he blows her hair dry and gives it it's final styling. (C) 's finished, he begins shaving the sides and ends by wearing a barber chair next to an instrument. (D) is finished, the woman goes inside and cliffs her hair to make the braid look interesting.
B

[header] How to make a positive impact on the lives of others [title] Find your own joy. [step] If you want to try to make others happy, then you'll need to start with yourself. What makes you happy? What brings you joy? Thinking about these questions will help you start to figure out how you can spread happiness to others. <sep> (A) [substeps] Make a list of the times you've been happiest in your life. It may help for you to go through a photo-book for this. (B) [substeps] Practice focusing on one thing at a time instead of fixating on all the other things around you. Try to focus on your own happiness and start to let it seep in and develop as you improve. (C) It will also help show how much effort you'll have to give to others. [substeps] Finding your own joy can be an easy process for you, if you're not skilled at it. (D) [substeps] Focus on the good things in your life. Do you enjoy doing the things that make you happy? If not, what is the most positive in your life? Find what makes you happy and put a positive spin on it.

A