The stage of the stress response in which the pituitary gland releases a flood of adrenocorticotropic hormones is

This is Alarm.

Explanation:

Adrenocorticotropic hormones and stress.

This the hormones secreted at the corticotrophs cells of the anterior pituitary glands.Its major function is to ensure the efficient functioning of the Adrenal gland and  body response to  stress.It is also mediate the secretion of cortisol from the cortex of the adrenal gland  into the blood stream.When it is released into the blood streams it binds to the receptors in the adrenal gland to stimulate the release of cortisol hormone.

ACTH controls  diurnal (circadian) rhythm in human.This is because it peaks in the morning and progressively reduced  towards the end of the day,with lowest concentration  during  period of sleeping.

Generally stress either by dehydration or  internal complications,leads to increase in solute potential of the blood.Stress increases the activation of ACTH from the adrenal gland while boosting the concentration of cortisol. When the stress is sensed by the brain,this causes the release of  corticotrophin-releasing hormone into the bllood.

The latter cause the discharge into the blood stream of ACTH via hypothalamic–pituitary–adrenal (HPA) axis.As this enters the blood it binds to the receptors  for the cortisol secretions in the cortex of the  adrenal gland to produce cortisol as explained earlier.Cortisol is the primary sex hormone which create the alarm.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.