Question

Is zero a rational number?

Answer 1

What is a rational number? 
Any number that can be written in $\frac{p}{q}$ form in which q ≠ 0.

Yes, 0 is a rational number because it can be written as $\frac{0}{1}$ in which the denominator ≠ 0.

Answer 2

Yes, zero is a rational number because it can be written in form of p/q as 0/1