[0.25, 1, 4, 16, 64]

Enter the values used in finding a partial sum. r =, a₁ =, n =

Select the explicit formula for the sequence.

a) Sₙ = 1 - rⁿ/1 - r
b) Sₙ = a₁ × rⁿ
c) Sₙ = a₁ × 1 - rⁿ/1 - r
d) Sₙ = a₁ + rⁿ