The compound interest on a certain sum of money for 2 years at 5% is Rs. 328, then the sum is = ?

Answer: Option C

For a first result cross check with option (Go with option (C) and check it.)
Principal is Rs. 3200
3200 of 5% for 1^st year = 160
then, principal = 3200 + 160 = 3360
3360 of 5% for 2^nd year = 168
∴ Interest = 160 + 168 = 328