Gavin has decided to start his own snow removal business. To purchase the necessary equipment, Gavin withdrew $2,000 from his savings account, which was earning 3% interest and borrowed an additional $4,000 from the bank at an interest rate of 7%. What is Gavin's annual opportunity cost of the financial capital that has been invested in the business. a. $340 b. $280 c. $60 d. $660