Two machines both have an average capacity of 200 units per hour and are functioning 80% of the time. Machine A is not down very frequently, but when it is down the outages are long. Machine B is down often, but when it is down the outages are short. Which machine do you select?

a). Machine A because its variability is higher.

b). Machine B because its variability is higher.

c). Machine A because its variability is lower.

d). Machine B because its variability is lower.