Here is your answer

REASON :
Integers are all natural numbers their negative including 0.
Rational numbers are the numbers of the form p/q where p and q are integers and q is not equal to 0.
So, the definition itself defines that every integer is a rational number.
Exa- Integers
1, -2 , 3, 90, -6
These are rational numbers as
1=1/1 (p/q form)
-2=-2/1 (p/q form)
3= 3/1 (p/q form)
90= 90/1 (p/q form)
-6= -6/1 (p/q form)
HOPE IT IS USEFUL