In Which Way Can Deletions Cause Abnormal Phenotypes

Multiple Choice

In which way can deletions cause abnormal phenotypes?

A) If the centromere is deleted,then the whole chromosome could be lost during meiosis.
B) In a heterozygous deletion,the gene dosage can be affected.
C) A recessive mutation could be expressed if the wild-type allele is deleted.
D) all of the above