Answer:
Option 1.
Explanation:
According to rational root theorem, all the potential rational roots of a function f(x) is defined as

where, p is a factor of constant term and q is the factor of leading coefficient.
The given function is

Here, leading coefficient is 9 and factors of 9 are ±1, ±3, ±9.
Constant term is 4 and factors of 4 are ±1, ±2, ±4.
All the potential rational roots of f(x) are

Therefore, option 1 is correct.