Which of the following statements are not true regarding functions choose all that apply

A. the horizontal line test may be used to determine whether a function is one-to-one

B. a function is a relation in which each value of the inut variable is paired with a least one value of the output variable

C. the vertical line test may be used to determine whether a function is one-to-one

D. a sequence is a function whose domain is the set of natural numbers