I = P x R x T / 100
WhereP = Principal
R= rate and T = time
$2000 was invested which is the principal
R = 3.5%, t = 4 years
I = 2000 x 3.5 x 4 / 100
I = 28, 000 / 100
I = $280
The interest after 4 years is $280
The balance inside the account is
B = I + P
Balance = 2000 + 280
Balance = $2280
The answer is $2,280