Two Researchers Select a Sample from a Population with a Mean

Multiple Choice

Two researchers select a sample from a population with a mean of 12.4 and a standard deviation of 9.Researcher A selects a sample of 30 participants.Researcher B selects a sample of 40 participants.Which sample is associated with a smaller standard error?

A) Researcher A's, because the sample size was smaller.
B) Researcher B's, because the sample size was smaller.
C) Researcher A's, because the sample size was larger.
D) Researcher B's, because the sample size was larger.