Distance equals velocity times time:
x = v*t = 1.7 m/s * 7.7min * 60 s/min = 785.4 m
Number of neutrons = atomic mass - number of protons
= 13 - 6 = 7
In short, Your Answer would be Option B
Hope this helps!
A.
Kinematics is independent of mass, in most cases.
