Not 100% sure but I'd go with A(:
The answer is A. Hepatitis B.
There are many primitive reflexes for infants, but some of them are the walking/stepping reflex (they will attempt to walk by abruptly placing one foot out), rooting reflex (looking for a base or the nearest object to latch onto because infants are always looking for the breasts to breastfeed from their mothers), and swimming reflex (if placed over water, the infant will paddle their arms and legs).
