QUESTION $13$

How is MTBF related to Failure Rate $($FR$)($failures per hour$)?$

a$.$

MTBF is measured in hours, while FR is measured in years

b$.$

MTBF is normally distributed, with FR as its mean and FR as its standard deviation

c$.$

MTBF is the reciprocal of FR

d$.$

Both MTBF and FR increase when breakdown maintenance is replaced by preventive maintenance

e$.$

MTBF and FR are unrelated concepts