Answer:
D) 11 m/s
Step-by-step explanation:
We have to calculate the velocity of the hot dog with respect to the observer still outside the train. This velocity will be given by:

where
is the velocity of the train (towards right)
is the velocity of the man (towards right)
is the velocity of the hot-dog (towards left, so we put a negative sign)
By replacing the numbers into the equation, we find

and the positive sign means the velocity is toward right.