A soft drink filling machine, when in perfect adjustment, fills the bottles with 12 ounces of soft drink. Any overfilling or under-filling results in the shutdown and readjustment of the machine. To determine whether the machine is properly adjusted, the most appropriate set of hypotheses is

A.H0: mu < 12; Ha: mu < or = 12

B.H0: mu < or = 12; Ha: mu > 12

C.H0: mu = 12; Ha: mu NOT = 12

D.H0: mu NOT = 12; Ha: mu = 12