The key to ensure the representativeness of samples in the lottery method is (a) making labels; B) mixing them evenly; C) Draw them one by one; D) draw them.

Solution: Because the key to ensure the representativeness of the sample in the lottery method is to mix evenly, it also ensures equal probability sampling. Choose B.

One-by-one sampling and non-return sampling are the characteristics of simple random sampling, but they are not the key to ensure representativeness. One-time sampling and sampling with replacement (the individual is repeatedly taken out but not put back) do not affect the representativeness of the sample, and the same is true for making labels, so choose sampling method A. ← Mathematical significance of each link.