What is the sum of the geometric series in which a1 = −5, r = 3, and an = −405?

Hint: r ≠ 1, where a1 is the first term and r is the common ratio.

Hint: Image attached

OPTIONS:

A) Sn = −1,220
B) Sn = 605
C) Sn = −15
D) Sn = −605