Lucy and Kevin’s mortgage protection

Cynthia is now a full-fledged actuary, working for an actuarial consulting company in Belgium. Her friends, Lucy and Kevin, call for help. They are about to buy an apartment, and will sign up for a 25-year mortgage to finance this apartment. Lucy and Kevin want to buy a financial product that covers the outstanding balance on the mortgage in case one of them dies before the mortgage is settled. What kind of product do they need?