Answer: it has a happy ending, often involving in a marriage.
Step-by-step explanation:
The option that defines a Shakespearean play as a comedy is that it has a happy ending, often involving in a marriage. It should be noted that being a comedy doesn't mean that the storyline should be funny.
Shakespeare's Comedies involve characteristics such as young lovers being faced with challenges, separation of the lovers and later reunification, mistaken identities, etc.