Explanation
Correct answer: C.
Choice C is the best answer. A comma is the appropriate way to link the dependent clause “While...not” and the independent clause that follows.
Why the other choices are wrong
Choice A
Choice A is incorrect. This choice creates a run-on sentence error. “While...not” is a dependent clause, which must be separated from the independent clause that follows with some sort of punctuation.
Choice B
Choice B is incorrect. This choice creates a sentence fragment. “While one requires oxygen and one does not” isn’t an independent clause, so it can’t stand alone as a complete sentence.
Choice D
Choice D is incorrect. This choice creates a punctuation error. “While one requires oxygen and one does not” isn’t an independent clause, so it can’t be linked to the clause that follows with a semicolon.