When Kian was born, his grandparents started a savings account for him with a beginning balance of $300. Every month they deposited $40 into the account. The savings account paid an annual interest rate of 2.1 percent, compounded monthly. Kian just turned 24 and the balance of his account is now $15458.67 How much of the money in Kian's account was earned in interest? (Round your answer to the nearest cent, and don't include the dollar sign.) Group of answer choices 3638.67 was gained by interest 2638.34 was gained by interest 11820.00 was gained by interest 9640.99 was gained by interest