Answer:
C.option 3
Step-by-step explanation:
We are given that Your boss tell you that she needs a decision by the end of the day about the machine you want to purchase for your new operation .
You have four choices , and your boss reminds you to be cost-efficient as possible but she wants the best efficiency .
Efficiency of machine : It tell us how much input energy converted into useful work.
Efficiency of machine= Output energy
input energy
In option 1 machine cost = $5000
The rate of supplied energy of machine =1900 W
The rate of useful work= 1786 W
Efficiency=

In option 2
Machine cost =$45,00
The rate of supplied energy of machine= 1450 W
The rate of useful work=1300 W
Efficiency=

In option 3
Machine cost=$14750
The rate of supplied energy of machine=1950 W
The rate of useful work=1833 W
Efficiency=

In option 4
Machine cost=$4750
The rate of supplied energy of machine=2000 W
The rate of useful work= 1822 W
Efficiency=

In option 1 and 3 cost are different but the efficiency of machine in option 3 and option 1 is same. But the cost of option 3 is smaller than the cost of machine in option 1. Hence, option 3 is best .
Answer: C.option 3