Final answer:
The correct revision that fixes the comma splice in the sentence 'Jessie painted a picture, she petted the cat' is option 4) Jessie painted a picture, then she petted the cat.
Step-by-step explanation:
The correct revision that fixes the comma splice in the sentence 'Jessie painted a picture, she petted the cat' is option 4) Jessie painted a picture, then she petted the cat.
A comma splice occurs when two complete sentences are joined by a comma without a coordinating conjunction or another form of punctuation. In this case, adding the coordinating conjunction 'then' creates a compound sentence, correctly separating the two ideas.