Answer:
B. I will finish my biology lab report before I start on my assignment for history.
Step-by-step explanation:
An independent clause is a clause or group of words that can stand on its own, have a meaningful sentence and can be used as a full sentence. On the other hand, a dependent clause is one which does not have the capability to be deemed a full meaningful sentence, and is not even able to stand on its own. Rather, it is always used alongside an independent clause to have its full meaningful sentence.
If a sentence begins with an independent clause, then there is no requirement for the use of a comma in the sentence. The phrase "I will finish my biology lab report" is the independent clause, for which the use of a comma is not necessary. Thus, the correct sentence where the independent clause comes first is -
I will finish my biology lab report before I start on my assignment for history.