A run-on sentence is a sentence having two independent clauses with improper punctuation and without conjunctions. The correct answer is option b. It is difficult to understand a run-on sentence because you cannot identify where to pause or stop and that the sentence does not have conjunctions which would help in the transition of clauses.
When a sentence have two or more subjects
The theme of the " The Birthday Box by: Jane Yolan " is
Do not let anything get in the way of living life to the fullest.