Which of the following is a run-on sentence?

A) The adventurer walked for days and days, for weeks on end, for what seemed like an eternity; he found himself in a state of perpetual exhaustion.
B) He is a little bit sour, she is a little bit sweet, and I am a little bit stale.
C) I left the room when he yelled at me.
D) Vote for Pedro he will represent you well.

Choice D is a run-on sentence because it combines two independent clauses without proper punctuation or conjunctions. The first clause, "Vote for Pedro," stands alone as a complete sentence, while the second clause, "he will represent you well," also stands alone as a complete sentence. However, there is no punctuation or conjunction to connect the two clauses or to separate them into two separate sentences.