Answer:
The capacity of the remaining bottles = 4 pints.
Step-by-step explanation:
6*3 + 6*b = 42
6b = 42 - 18
6b = 24
b = 4.
If you mean
, then the derivative is

If you mean
, we know from above that

which leaves the constant term, whose derivative is

and so

Answer: Most likely (A) and (D)