Under Which Condition(s)would Genetic Testing for Predisposition to an Inherited

Under which condition(s) would genetic testing for predisposition to an inherited disorder in a minor child be considered reasonable?

A) When the family pedigree indicates an autosomal dominant pattern of inheritance
B) When the risk is high and prophylaxis to reduce disorder severity is available
C) When penetrance is high and the expected onset is middle adulthood
D) When the mutation within a family is known and is specific