Which of the following is the graph of y=sec x?

The graph of y=sec x has a period of 2π and has vertical symptotes where sec x is undefined, that is where cos x =0 (all x except for π/2 + multiples of π). Therefore, the graph of y=sec x should have vertical asymptotes at x=…-π/2, π/2, 3π/2…etc. At x=0,y= sec 0=1.