The correct answer is C, 30 days. Massachusetts requires the landlord to return the security deposit, or the lawful remaining balance after permitted and properly documented deductions, within thirty days after termination of the tenancy.

Permitted deductions can include unpaid rent that was not lawfully withheld, qualifying unpaid real estate tax increases where a valid tax-escalator clause applies, and reasonable repair costs for tenant-caused damage beyond ordinary wear and tear.

The statutory documentation requirements matter. A landlord cannot simply deduct a round number for “repairs” without following the required procedure.

Failure to return the deposit properly or comply with the statutory deposit requirements can expose the landlord to significant remedies, potentially including multiple damages and attorney ' s fees.

The 30-day period is therefore a critical Massachusetts exam figure and should be distinguished from notice periods applicable to terminating a tenancy at will.

Study Guide Reference: Property Management — Security Deposits, Deductions and Return Requirements.