Answer
$P$(System B fails to operate properly) = $3.61$%
Work Step by Step
$P$(System B operates properly)= $0.9639$ (as per part c of the question)
$P$(System B fails to operate properly)= $P$(System B operates properly$)^{c}$
$P$(System B fails to operate properly)= $1-0.9639$
$P$(System B fails to operate properly)= $0.0361$