True about cystic hygroma -
Answer is 'a' i.e. Congenital sequestration of lymphatics "Bailey writes that spontaneous regression may occur in cystic hygroma but I am not sure whether it occurs by 5 yrs of age".
Congenital sequestration of lymphatics
Resolves spontaneouly by 5 year of age
Common in upper 1/3rd of lateral neck
All