Which of the Following Is an Explanation

Multiple Choice

Which of the following is an explanation?

A) He straightened his tie carefully, as he did every morning.
B) Since cheerleading is physically demanding, it should be considered a sport.
C) Since the blizzard of 2002, it has never snowed in our town.
D) The boss always rewards hard work, but punishes laziness.
E) Amanda was able to buy a new car because she got a promotion at work.