Final answer:
The correct answer is Option A. In negative feedback mechanisms, changes that move a variable away from the normal state are countered by stimulating a change in the opposite direction to bring the variable back to normal.
Step-by-step explanation:
In negative feedback mechanisms, when changes move a variable away from the normal state, the body stimulates a change in the variable in the opposite direction to bring it back to the normal state. This is the main role of negative feedback loops in maintaining homeostasis. For example, if blood glucose levels rise, the body releases insulin to decrease blood glucose levels, and if blood calcium levels decrease, the body releases parathyroid hormone to increase blood calcium levels.