b) yes
step-by-step explanation:
let the statements be named as,
statement 1: if the power has been cut, then the refrigerator does not work.
statement 2: the refrigerator does not work.
conclusion: the power has been cut
now, 'law of detachment states that if we have the statements given as,
1. if p, then q.
2. p
then, we get the true statement or conclusion as q'.
thus, on comparing, we get that,
p: if the power has been cut.
q: the refrigerator does not work.
so, the argument is true by the law of detachment.