Of the Given Values Of $x$ , Identify Those at Which the Function Is Continuous

Multiple Choice

Of the given values of $x$ , identify those at which the function is continuous.
- $f(x) =7 x^{4}-9 x^{3}+x-4 ; x=4,0,9$

A) $4,0,9$
B) 0,9
C) None
D) 4,0