Answer:
Option (I) has the lowest energy rate so that would be best option.
Step-by-step explanation:
(I). Given that,
Input energy = 1900 W
Output energy = 1786 W
We calculate the loss of energy
Using formula of loss of energy

Put the value into the formula

(II). Given that,
Input energy = 1450 W
Output energy = 1300 W
We calculate the loss of energy

(III). Given that,
Input energy = 1950 W
Output energy = 1833 W
We calculate the loss of energy

(IV). Given that,
Input energy = 2000 W
Output energy = 1822 W
We calculate the loss of energy

Hence, Option (I) has the lowest energy rate so that would be best option.