Answer: Hello mate!
The notation:
a < b
means that the number b is bigger than the number a, and the notation:
a ≤ b
means that the number b is bigger or equal than the number a.
"all real numbers y that are less than 4"
this is written as:
y < 4
"all real numbers that are greater than 9"
this is written as:
y > 9
then, the situation can be written as:
y <4 and y >9, which means that the right answer is option C.