The Figure Shows a Side View of a Galaxy That

The figure shows a side view of a galaxy that is 50.0 light years in diameter. This value for the diameter is its proper length. A spaceship enters the galactic plane with speed 0.995c relative to the galaxy. Assume that the galaxy can be treated as an inertial reference frame. Note: A light year is the distance that light travels through vacuum in one year; that is, 1 light year = c × (1 year) .
-How long does it take the spaceship to cross the galaxy according to a clock on board the spaceship?

A) 5.02 years
B) 12.5 years
C) 49.8 years
D) 50.3 years
E) 90.0 years