[A] is the only logical answer, as the y coordinate of the vertex on a sec graph is 1 and -1, but in this case, it's 3 and -3. This means we've multiplied the value of y by 3, indicated by the 3 before the sec on answer [A].
Answer [B] would be dividing the value of y by 3, not multiplying.
Answer [C]'s transformation on y is adding 3 the values, which would be 4 and -4 for the vertex coodinates.
Answer [D] is not a trigonometric function.