Answer:
option B : 
Step-by-step explanation:
(a) 
For exponential function , there is no vertical asymptotes
General form of exponential function is


In the given f(x) the value of k =0
So horizontal asymptote is y=0
(b) lets check with option

To find vertical asymptote we set the argument of log =0 and solve for x
Argument of log is x-39
x-39=0 so x=39
Hence vertical asymptote at x=39