Answer:
B, C, D are functions
Step-by-step explanation:
Functions are those that do not share an x value. Look at A. x-values are used twice everywhere except the vertex. This is not a function, it is just a relation. B does not at any time share x-values, so this is a function. C is also a function, and so is D. F is a vertical line that shares the same x value throughout the whole line, so this is definitely not a function.
