The correct answer is B, Adjustable-rate mortgage (ARM). An ARM has an interest rate that can change after specified intervals based on the loan ' s contractual formula.

The formula typically references an index or benchmark and adds a lender ' s margin. The note also commonly includes adjustment periods, initial-rate periods, periodic caps, and lifetime caps designed to regulate how much the rate and payment can change.

A fixed-rate mortgage maintains the same contractual interest rate for the loan term. A blanket mortgage covers multiple parcels. A reverse mortgage involves a different equity-based financing arrangement for eligible borrowers.

ARMs can initially offer lower rates than comparable fixed-rate loans, but borrowers assume interest-rate risk because future payments may rise if the applicable index increases.

Massachusetts Board financing curriculum specifically includes adjustable-rate mortgage loans among the mortgage types candidates are expected to understand.

Study Guide Reference: Financing — Adjustable-Rate Mortgages, Indexes, Margins and Interest-Rate Adjustments.