Answer
4/9 belongs to rational numbers (D).
Explanation
(Lol moderator deleted everyone's answers so I'm gonna answer).
First I'll give you a definition of each choice.
Integers: Integers don't include decimals or fractions. Integers are positive and negative numbers. So basically it's this; (..., -3, -2, -1, 0, 1, 2, 3, ...). The '...' means numbers from infinity to the next number. I hope this makes sense Imao.
Whole numbers: whole numbers are integers, except they don't include negative numbers. Whole numbers include 0 (zero)... (0, 1, 2, 3, ...)
Natural numbers: natural numbers are whole numbers but they don't include 0 (zero)... (1, 2, 3, ...)
Rational numbers: rational numbers are numbers that can be expressed as a fraction. This includes repeating decimals such as 0.333 repeating. Rational numbers also include integers, because if you put the number over one, that is a fraction. Rational numbers are basically every number except for the radicals of some numbers (such as the square root of 3) and pi.
So now let's just see which one 4/9 is.
Well, 4/9 is not an integer, whole number, or natural number because it is a fraction.
But 4/9 can be expressed as a fraction (well, it already is one) meaning it is a rational number.
=18