A couple bought their first home, qualifying for a 30-year loan. The lender required regular, equal payments of sufficient size and number to pay all interest due on the loan and reduce the amount owed to zero by the loan's maturity date. This is most likely

A partially amortized loan involves payments that do not fully pay off the principal by the loan's maturity. Instead, at the end of the term, a balloon payment is required to settle the remaining balance. This type of loan does not meet the criteria of reducing the amount owed to zero through regular payments.

An Adjustable Rate Mortgage (ARM) features fluctuating interest rates that can change at specified intervals, affecting the payment amounts. While ARMs can be structured as fully amortized loans, the critical aspect here is the requirement for equal payments, which does not inherently apply to ARMs due to their variability.

A straight loan, or interest-only loan, requires the borrower to pay only the interest during the term, with the principal due at maturity. This structure does not involve regular payments that reduce the principal balance, thus failing to meet the requirement of reducing the amount owed to zero by the loan's maturity date.