Final answer:
Buyer Barbara is typically responsible for the payment of discount points to buy down the interest rate on her mortgage, though the seller can agree to pay a portion or all of it during sales negotiations.
Step-by-step explanation:
The question pertains to who is responsible for the payment of discount points when buying down the interest rate on a mortgage. The answer is (a) Buyer Barbara. In a home purchase, discount points are an upfront payment made to the lender at closing to secure a lower interest rate on the mortgage. The buyer typically pays this fee, though in some cases, the seller may agree to pay a portion or all of it as part of the sales negotiation. However, this would need to be agreed upon before closing; it is not a standard practice. Barbara's lender is offering the discount points, but it is ultimately Barbara's responsibility to pay for them if she chooses to utilize this option to reduce her interest rate.