A major credit card company is launching a referral program, which gives an existing customer $50 for each new customer he or she refers to the company. The credit card company estimates that the average annual spending of a customer is $15,000, and the revenue for the credit card company would be 5% of the spending. The estimated marketing and operations costs for the referral program is $500,000 per year. a. Build a spreadsheet model for the credit card company to estimate the annual increase in profit gained from the referral program. If the referral program helps the credit card company acquire 25,000 new customers, what is the annual increase in profit gained from the referral program. Assume all new customers are acquired at the beginning of the year. b. It is estimated that 10% of the customers acquired through the referral program would have become customers of the credit card company even without the referral program. How does this information change the spreadsheet model and the annual increase in profit gained from the referral program?