What Did Research Carried Out by Herbert, Gross & Hayne

What did research carried out by Herbert, Gross & Hayne in 2006 demonstrate regarding deferred imitation?

A) That the longest that a child under 14 months of age can defer imitation is 3 - 4 hours.
B) That a 14 month old can defer imitation for up to a week.
C) That deferred imitation doesn't happen until at least 18 months of age.
D) That nine-month-olds can defer their imitation for as long as 24 hours.