Answer: Option 4
Explanation: "Juliet can be quite pleasant at times" and "she can get really stressed out at work." are both independent clauses, meaning they can stand on their own as sentences. These two clauses are connected by a conjunction, which is in this case "however." There will almost always be a comma after the conjuction in a connection between two clauses, so option 1 and 2 are immediately wrong. A ";" never goes after a comma in a sentence unless there is another conjuction (which in this case there isn't) so the answer is option 4.