Final answer:
An acceleration clause benefits the mortgagee by allowing them to require immediate repayment of the loan if the borrower violates terms such as missing payments.
Step-by-step explanation:
The acceleration clause gives the mortgagee the right to declare the entire outstanding mortgage debt due and payable immediately if the mortgagor (borrower) breaches certain terms or conditions of the mortgage contract. Question asks whose interest is benefitted by an acceleration clause in the context of a mortgage. An acceleration clause is a provision that allows the lender, the mortgagee, to require immediate payment of the entire loan balance if certain conditions are violated, such as missing payments. Therefore, the party whose interest is benefitted by an acceleration clause is (b) the mortgagee.