Use the sequence {−1,171,875;−234,375;−46,875;−9375, …} to answer the question.

What is the explicit rule that describes the sequence?

an=−1,171,875(125)n−1
an=1,171,875(−15)n−1
an=−1,171,875(15)n−1
an=1,171,875(−115)n−1