How does the effective start date of a record affect valid When associations?

How does the effective start date of a record affect valid When associations?
A . You can only associate records when they were created the same day
B . You can associate a child record that precedes the parent’s effective start date
C . You can associate records with the same effective start dates
D . You can associate a child record if it is after the parent’s effective start date

Answer: C, D