What is the definition of an irrational number?

A.
a number that can be written as a fraction but not as a decimal

B.
a negative number

C.
a number that can be expressed as a fraction, , where p and q are integers and q is not equal to zero

D.
a number that cannot be expressed as a fraction, , where p and q are integers and q is not equal to zero

Answer :

A.

a number that can be written as a fraction but not as a decimal I think