A Problem with the Original Studies Suggesting That the Sense

A problem with the original studies suggesting that the sense of taste declines with age was that:

A) evaluating taste was difficult,because appropriate technology for such experiments did not exist.
B) age-related loss in taste results from declines in both taste buds and olfactory receptors.
C) the studies included many individuals who were sick or had specific age-related diseases that affect taste.
D) the cohort effect introduced errors.