It's time for Margaret to give her baby his bath. The water is warm and she adds bubble bath to the water. When she puts her baby in the water, the baby splashes around and plays with the bubbles, and genuinely appears to enjoy himself because his is/are being stimulated.
Select one:
a. curiosity
b. brain
c. socialization skills
d. sense organs

Option D, sense organs

Explanation:

Since the sense organs of the baby are active, he/she could feel the warmth of the water. He/she could view the bubbles formed in the water which on touching are splashing/bursting. Here the baby is utilizing his/her eyes  for seeing the bubbles and hand (skin) to burst them. Since, the baby is able to sense all the pleasures and sensations associated with bathing in warm water, he/she is enjoying.  

Hence, option D is correct

1.the evidene of the reaction

2.yes

3.yes