The answer is B.
The factor by which 2 changed to -10 is \(\frac{-10}{2},~or~-5.\)
The change for the next term is \(\frac{50}{-10},~or~also~-5.\)
Again, the change to the next term is \(\frac{-250}{50},~being~-5.\)
Since the terms are consistently increasing by -5, that is your ratio. Your answer is B, -5.