If you divide a force measured in newtons by a speed measured in in meters per second in what units will the answer be expressed

'Newton' is [ kg·m/s² ].

So if you divide Newtons by [ m/s ], it goes something like this:

(kg·m/s²) / (m/s) =

(kg·m/s²) · (s/m) =

(kg·m·s / m·s²) =

kilogram / second .

This is an interesting exercise in manipulating units, but it doesn't seem to mean anything in the real world.  

We performed one meaningless operation ... dividing force by speed ... and ended up with another quantity that has no physical significance ... kilogram per second.

your answer is c! hope this : )