How far apart can optical amplifiers be spaced if they can amplify a signal 25 dB, and the cable looses 0.25 dB every kilometer?

How far apart can optical amplifiers be spaced if they can amplify a signal 25 dB, and the cable looses 0.25 dB every kilometer?

A.
10 miles

B.
25 miles

C.
60 miles

D.
80 miles

E.
100 miles