Given the accumulation formula a(t), which of the following formulas gives the accumulated value at time 4 of four deposits of 10 made at times 1, 2, 3, 4/
a. 10 [a(4)/a(1) + a(4)/a(2) + a(4)/a(3) + 1]
b. 10 [a(3) + a(2) + a(1) + 1]
c. 10 [a(1) + a(2) + a(3) + a(4)]
d. 10 [1/a(1) + 1/a(2) + 1/a(3) + 1/a(4)
e. 10a(4)
