When a man running on a levelground increases his speed by 4ms^(-2), if his kinetic energy increases by 125% his initial velocity is

When a man running on a levelground increases his speed by 4ms^(-2), i

1.	When a man running on a levelground increases his speed by 4ms^(-2), if his kinetic energy increases by 125% his initial velocity is
Answer» `4 ms^(-1)` `8 ms^(-1)` `2ms^(-1)` `6 ms^(-1)` ANSWER :B