I need help with this problem please.

Phlight Restaurant is considering a delivery service. The firm expects that sales from the new service will be $150,000 per year. Phlight currently offers a sit-down service with annual sales of $100,000. While many of the delivery sales will be to new customers, Phlight estimates that 60% of their current sit-down customers will switch and use the delivery service. The level of incremental sales associated with introducing the delivery service is closest to: Select one: a. $90,000 b. $150,000 c. $60,000 d. $120,000