How fast will a cart be moving if a force of 200 n is applied to a 50 kg cart for 10 sec?

I'm assuming that the cart starts from rest.

Initial velocity (vi): 0 m/s
Final velocity (vf): ?
Acceleration (a): ?
Force (F): 200 N
Mass (m): 50 kg
Time (t): 10 s

F= ma
200 N= (50kg)(a)
a= +4 m/s^2

a= (vf-vi)/t
+4 m/s^2= (vf - 0m/s)/10s
vf= 40 m/s

the cart will be moving 40 m/s.

Ithink the answer is c but then again i'm probably wrong