Which of the Following Is What We Expect If the Samples

Which of the following is what we expect if the samples we use in an ANOVA come from populations with the same means?

A) The error mean square will be identical to the group mean square.
B) The error mean square will be larger than the group mean square.
C) The error mean square will be smaller than the group mean square
D) The error mean square will be very close to than the group mean square.