Answer:
the second one
Step-by-step explanation:
well first lets find out what a run on sentence is
a run on sentence happens when two or more independent clauses are connected without using a comma, semi colon or a colon
in the sentence I went to the park then I went home there are two independent clauses, I went to the park and I went home. these independent clauses are not connected properly therefore this is the run-on sentence