Correct option (a) Barr bodies
Explanation
Females have XX-chromosome, presence of Barr body indicates female child while absence indicates male. Amniotic fluid contains living cells flaked off from the skin of baby or amnion (derived from zygote and identical to foetus cells).
The non-dividing cells are examined. One X-chromosome always appears in the active state. If another is present, it is seen in a resting state as tightly coiled dark staining body (Barr body).
