A buffer solution

Question

A. contains approximately equal amounts of a weak acid and its conjugate base.
B. increases its properties with an increase in the concentrations of the two buffer components.
C. resists changes in pH.
D. all of the above
I got C is that correct, to is it D?
Thanks

Answer 1

I don't know what the answer is because I don't know what "approximately" in A means. Some buffer solution may have as much as 10x as much acid as conjugate base. Is that approximate or not? If A is true (and I know B and C are true), then D is the answer. Otherwise, if there is only one answer how do you choose between two correct answers.
So my best guess is this.
If there is only one correct answer, then D must be the only one to choose since both B and C are true and that makes A true by way of reason.