Answer:
 c.  1.4×10^5 N
Explanation:
Work is the product of power and time. It is also the product of force and distance. We can equate these two products to find the distance.
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 Wt = Fd
 (7.0×10^4 N·m/s)(40 s) = F(20 m)
 F = (7.0×10^4)(40/20) N = 1.4×10^5 N
The force exerted by the motor is 1.4×10^5 newtons.