A running man has half the KE that a body of half his mass has. The man speeds up by `1.0ms^(-1)` and then has the same energy as the boy. What were the original speeds of the man and the boy?
A. `sqrt(2)m//s`
B. `(sqrt(2)-1)m//s`
C. `(1)/((sqrt(2)-1))m//s`
D. `(1)/(sqrt(2))m//s`