Which describes a random selection procedure?

I believe the correct answer is B. We are looking at the relative frequency of letters, and you are choosing a random sample of books to count it.
With respect to a random sample, we sample from a population. We like to randomly select a sample from a population. Thank you.

If it is a MCQ, I would choose D. as my interpretation of "random selection procedure" is to ensure that each respondent has the same chance of being selected into the sample.

in D, the goal is to have a sample test whether the products are produced according to the expected value.

A = to me is an intended selection
B = to me is the making of observation so as to make a conclusion on the frequency of letters used in the book.
C = to me the purpose of the selection is not clear