Shown is the graph of the function
`f:R - {0} rightarrow R ` defined by, `f(x) = frac{9-x^2}{9x-x^3}`.

Based on the above function, two statements are given below - one labelled Assertion (A) and the other labelled Reason (R). Read the statements carefully and choose the option that correctly describes statements (A) and (R).
Assertion (A): The function f is not onto.
Reason (R): 3 `in` R (co-domain of f) has no pre-image in the domain of f.

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true but R is false.
D. Both A and R are false.