Answer:
C ) [tex]\frac{9}{\sqrt{31}}[/tex]
Step-by-step explanation:
An Irrational number is any number that can't be written as [tex]\frac{a}{b}[/tex] because it is not a terminating one.
In this case, [tex]\sqrt{31}[/tex] which is an irrational number since there is no perfect square root of [tex]\sqrt{31}[/tex]. Then the outcome is another irrational number too.
Proof:
[tex]\frac{9}{\sqrt{31}}=1.616447718...[/tex]
