Stress is 1. something that can be completely eliminated from a person's life.
2. series of physical and psychological reactions that occur when you respond to a demanding or threatening situation.
3. a cascade of hormones that prepare your body to face a physical threat.
4. always harmful to an individual's long-term health.

The answer is 2:  A series of physical and psychological reactions that occur when you respond to a demanding or threatening situation.

Explanation:

Process of elimination:

1 - You can never completely eliminate stress

3 - Stress doesn't always manifest for a physical threat, it can form because you have a test next period or because you have an upcoming project,

4 - Stress is not always harmful, it also can come and go and you might even feel better afterwards, as in cases of physical stress.

the answer is c, the development of reading and writing in young children