Answer: Option A
Explanation: The screaming of the child is reducing his balanced state. Parents are also in stress, which disturbs their equilibrium state. So its a case of negative feedback.
It is not a case of positive feedback because screaming of the child or stress of the parents is not decreasing. It is not causing any balance in the body, so its not a positive feedback. Here we are not putting anyone into a condition of adversity, so there is no case of survival. So option C is incorrect. The state of the child and the parents is not balanced, so its not option D.
