Why Is Much of the Evidence About the Effects of Spanking

Multiple Choice

Why is much of the evidence about the effects of spanking considered to be controversial

A)  Most of the studies are correlational, which does not allow for conclusive statements about cause and effect. 
B)  Although there is a lot of anecdotal data regarding the risks of spanking, there are no studies with large sample sizes. 
C)  Most of the studies have been conducted on children with pre-existing behaviour problems. 
D)  Because most adults have experienced corporal punishment, it is next to impossible to find a sample for the control group.