What Best Explains Why Older Adults Are at Higher Risk

What best explains why older adults are at higher risk of drug interactions with herbal supplements? ​

A) Older adults are more likely to take more than three different medications at a time.
B) The bodies of older adults cannot process herbal supplements at all.
C) Older adults do not always understand how to buy the correct supplements for what they need.
D) The herbal supplements provided to older adults are more likely to have fillers and toxic agents.