Answer:
4.) 5.3333333....
Explanation:
Rational numbers are either repeating decimals:

Include terminating decimals:

Are all numbers that can be written as a quotient of integers:

Options (1), (2), and (3) are neither repeating, terminating, and can't be written as a quotient of integers.
Option (4) has repeating decimals, so this is rational.
:Done