Answer
$\epsilon = 5.71 %$
so choice (a) is correct.
Work Step by Step
The plant's actual efficiency is
$\frac{W}{t} = 10 MW$
$\frac{Q_C}{t} = 165 MW$
$\frac{Q_H}{t} = \frac{W}{t} + \frac{Q_H}{t} = 175 W$
$\epsilon = \frac{\frac{W}{t}}{\frac{Q_H}{t}}$
$\epsilon = \frac{W}{t} \times \frac{t}{Q_H} $
$\epsilon = \frac{W}{Q_H} $
$\epsilon = \frac{10 MW}{175 MW}$
$\epsilon = 5.71 %$
so choice (a) is correct.
