What Is True About All Post-Hoc Tests Such as Tukey's

Multiple Choice

What is true about all post-hoc tests such as Tukey's HSD Test and Scheffé's Test?

A) Each group mean is compared to each other group mean
B) It shows the overall effect of the groups on a variable
C) It is done regardless of whether the one-way ANOVA's F test result is significant or not
D) It is done prior to the ANOVA's F test