Choose the One Alternative That Best Completes the Statement or Answers

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
Determine whether the sequence is geometric. If so, find the value of r.
- $$\frac { 15 } { t ^ { 4 } } , \frac { 75 } { t ^ { 8 } } , \frac { 375 } { t ^ { 12 } } , \frac { 1,875 } { t ^ { 16 } }$$

A) geometric, $r = \frac { 5 } { t ^ { 4 } }$
B) not geometric
C) geometric, $r = \frac { 15 } { t ^ { 4 } }$
D) geometric, $r = \frac { 1 } { t }$