Answer:
A variable cubed:

Quotient of some number and 3:

Product of an unknown number and 3:

Three less than a variable:

Three more than some number:

Explanation:
A variable cubed:
This implies that a variable multiplied by itself in 3 places
From the list of options,
answers this question because;
; i.e. x multiplied by itself in 3 places
Quotient of some number and 3:

The quotient of a number means the division of a number by another number;
Represent the number with b;
When divided by 3; the quotient is

Product of an unknown number and 3:

This means 3 multiplied by a number;
Represent the unknown number with a;
This implies that

Three less than a variable:
This means that we subtract 3 from a variable;
Represent the variable with y
This implies that

Three more than some number:
This means that we add 3 to a variable;
Represent the variable with z
This implies that
