Correct Answer - B
If target is at rest, then final velocity of bodies are
`v_(1) = (m_(1)-m_(2))/(m_(1)+m_(2))u_(1)`...................(i)
and `v_(2) = (2m_(1)u_(1))/(m_(1)+m_(2))`.................(ii)
From eqs (i) and (ii), `v_(1)/v_(2) = (m_(1)-m_(2))/(2m_(1)) = 2/5 rArr (m_(1))/(m_(2)) = 5`