The amount of power has decreased. this is most likely the result of less work being done over a longer period of time.
less work being done over a shorter period of time.
the same amount of work being done over a longer period of time.
the same amount of work being done over a shorter period of time.

Option (A)

Explanation:

Power is defined as the rate of doing work.

Or

The work done in unit time is defined as the power.

The formula for the power is given  by

Power is a scalar quantity and its SI unit is Watt.

As the power is decreased, either work is decreased or time is increased.

So, if a less work is done in a longer period of time, the power is decreased.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

b.

hope this : )