I've looked this question up, and this is the excerpt it refers to:
(1) Roller derby is a high contact extreme sport that began in the United States during the 1920s. (2) This sport takes place on a long oval track. (3) Participants earn points by skating past, or "lapping," members of the other team. (4) Roller derby is primarily played by women, and most skaters are amateurs who raise their own support in order to participate. (5) Many skaters wear fun costumes and adopt fake names to express their personalities. (6) Because many injuries can occur at roller derbies, emergency medical personnel are required to stay rinkside, and skaters must wear protective gear at all times.
Answer:
The best way to combine sentences 1 and 2 is:
A. Roller derby is a high contact extreme sport that began in the United States during the 1920s, and this sport takes place on a long oval track.
Step-by-step explanation:
Option B uses the conjunction "while" unnecessarily. When we read the sentence, we feel there should be more information afterward, because of the presence of "while". We can eliminate option B for that reason.
Options C and D are also incorrect. They are both run-on sentences. Option C does not use any conjunctions to connect the two independent clauses. Option D does use a conjunction, but no punctuation.
Option A is the best choice. It uses a coordinating conjunction to connect the independent clauses, as well as proper punctuation:
A. Roller derby is a high contact extreme sport that began in the United States during the 1920s, and this sport takes place on a long oval track.