A. True. Plug in x = 0 and it leads to y = 1.
B. False. The function is undefined when cos(x) = 0 which is when x = n*pi/2 for any odd integer n. So x = pi/2, x = 3pi/2, x = 5pi/2, etc are not allowed as input values.
C. True. This is one of the infinitely many vertical asymptotes, which result from to the fact that x = pi/2 is not allowed in the domain.
D. False. Sine can be equal to zero. The only thing we need to make sure that is nonzero is the cosine value, since secant = 1/cosine
E. False. Choice B talks about values excluded from the domain.
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In summary, the answers are Choice A and Choice C