Hoping to Get Information That Would Allow Them to Negotiate

Hoping to get information that would allow them to negotiate new rates with their advertisers,
Natural Health magazine phoned a random sample of 600 subscribers. 64% of those polled said they
Use nutritional supplements. Which is true?
I. The population of interest is the people who read this magazine.
II. "64%" is not a statistic; it's the parameter of interest.
III. This sampling design should provide the company with a reasonably accurate estimate of the
Percentage of all subscribers who use supplements.

A) I only
B) I and III only
C) II and III only
D) I and II only
E) I, II, and III