Answer:
The answer is A. Somatic cells of a female only.
Explanation:
Barr's body or Barr's corpuscles, also called sex chromatin X, are a heterochromatic mass found in the nucleus of female somatic cells. According to the Lyon hypothesis (Mary Lyon, 1966) one of the 2 X chromosomes in each female somatic cell is genetically inactive. The corpuscle of barr represents the inactive X chromosome.