Let $f(x) = \frac{x^2 - 9x + 20}{x^2 - 4x}$ Complete parts (a) through (c) below.
b. Does the graph of $f$ have any vertical asymptotes? Select the correct choice below and, if necessary, fill in the answer box(es) to complete your choice
A. The graph of $f$ has two vertical asymptotes. The leftmost asymptote is and the rightmost asymptote is
(Type equations.)
B. The graph of $f$ has one vertical asymptote at
(Type an equation.)
C. The graph of $f$ has no vertical asymptotes.
c. First, graph $f$ using a graphing utility. Choose the correct graph below.