Researchers Studied Pain Among a Sample of 1200 Hospitalized Patients

Researchers studied pain among a sample of 1200 hospitalized patients. Study participants were divided into three age groups to assess differences in distress from pain (scale of 0-10) . Which test would be appropriate?

A) A paired t-test was appropriate because the patients were all from the same hospital.
B) An independent t-test because the age groups are not related.
C) ANOVA because three groups are being compared and the outcome variable is at a ratio level.
D) Repeat measures ANOVA because the subjects got one year older annually and the act as their own control group.