B. Is the correct answer, however if this happens over a long period of time, it will develop into C.
A. Age
Age is the best answer because it is easily determined and since there are stages of development, age can tell staff other things such as coordination level, ability and risk of getting hurt.
I'll go through the other answers briefly.
B. Intelligence. Intelligence is a fair enough answer, save for the fact that it is something that is not easy to determine quickly and hence, it would be difficult to determine each child's intelligence before they came into the daycare. Furthermore, intelligence or lack thereof does not necessarily mean that the child does not need as much supervision.
C. Previous training. This is not the correct answer because it is the previous training "of the children cared for." The children do not need to have previous training. It could work as an answer if it were in relation to the workers, not the children.
D. Coordination. Somewhat of a good answer. However, once again, coordination is not an easy determinant, and cannot always reliably predict how many staff should be with how many children.
During stress, hormones like epinephrine and norepinephrine are secreted at higher levels. The sympathetic nervous system is also activated at that time. There is also an increase in blood pressure and improper insulin-dependent glucose disbursal. All of these lead to insulin resistance, and central obesity. Vascular complications also increase. The Basic Metabolic Rate (BMR) lowers down during the same because of disruption in the digestive system.
The leaked fluid is being absorbed by pathogens and dead cells, so when the fluid is returned to the blood, the body can stabilize its internal conditions (homeostasis.)
If you give me the answer choices I’ll comment under this :)
