Your hypothesis is incorrect considering every day has the same length to it.
I believe the answer is <span>c. absorption
</span>The phase of pharmacokinetic that happens in the intestine is when the drug absorbed. A person with old age will have lower intestine motility. This will increase the transit time which will increase the amount of drug absorbed.
Age could also influence others pharmacokinetic parameter(<span>excretion, distribution, metabolism) but it is related with another organ, not intestine.</span>
Answer:
Not able to see anything so please click it clearly.
You may have to enlarge it but here you go!