(10 points) For the amount function A(t) = + 4t+ 6, the corresponding accumulation function a(t) and the nth period's interest rate i,, are: 2n+3 n+4n+6 A. a(t)=1/1 +41 + 1, fn = O B. a(t)=2+t+1. in O c. a(t)=+1, in= O D. a(t)-t + 4t + 6, in = 2n+3 n+4n+6 2n+3 n+2+3 2+3 n +2+3 E. a(t)=+ +1.1, 2n +3 =