The Following Samples Were Selected by Two Researchers $\mu$ = 8 $\sigma$

Multiple Choice

The following samples were selected by two researchers.Which is associated with a smaller standard error of the mean?
Researcher A: n = 18, $\mu$ = 8, $\sigma$ = 2.4
Researcher B: n = 12, $\mu$ = 8, $\sigma$ = 2.4

A) Researcher A.
B) Researcher B.
C) They both have the same standard error.