Hello! 3.5% in decimal form is 0.035. You add 1 to that to get 1.035. B is out, because that number is too high. A is out, because it doesn't add 1. The formula for compound interest is P(1 + r)^t. D is also out, because it incorrectly interprets 3.5% in decimal form. The correct form is 3,500(1.035)^t. The only one that shows this is C. Therefore, the answer is C.