According to the Fair Labor Standards Act $($FLSA$)$ regulations, which of the following employees could work for no more than $3$ hours on a school day?

Question $6$ options:

a$)$

an employee that is $18$ years old

b$)$

an employee that is $14$ years old

c$)$

an employee that is $15$ years old

d$)$

an employee that is $16$ years old

e$)$

both b and c

f$)$

all of the above