Shawn Is 5 Years Old and Sucks His Thumb

Shawn is 5 years old and sucks his thumb.His mother is worried that thumb sucking will become a lifelong habit.A developmental psychologist would MOST likely advise Shawn's mother to:

A) keep Shawn at home for another year before entering kindergarten.
B) change her disciplining methods.
C) develop a strict behavior intervention plan.
D) relax because the behavior will most likely remit on its own.