Question 18 of 25 Which of the following statements are not true regarding functions? Check all that apply. O A. A function is a relation in which each value of the input variable is paired with at least one value of the output variable. B. A sequence is a function whose domain is the set of natural numbers. I C. The vertical line test may be used to determine whether a function is one-to-one. OD. The horizontal line test may be used to determine whether a function is one-to-one.​