Which of the following sentences is grammatically correct?

Question

Quizplus · Accepted Answer

Run-on sentences are when two or more complete sentences are written as one sentence. Run-on sentences can be fixed by adding a dash (-), a semicolon (;), or a colon (:) between the two sentences. You could also add a coordinating conjunction with a comma (, but) or make them two separate sentences with a period (.).
These would be correct:
The weather forecast said it was going to rain - it was sunny the whole weekend.
The weather forecast said it was going to rain; it was sunny the whole weekend.
The weather forecast said it was going to rain. It was sunny the whole weekend.

Which of the Following Sentences Is Grammatically Correct