7. Which relation is a finction? A. \( (2,7,(4,5)(4,4)(2,3),(2,1) \) B. \( (1,1)(2,2 \lambda(2,3)(4,4)(5,8) \) C. \( (2,-3)(2,3)(4,-2)(4,2)(40) \) D \( (1,0)(2,0)(1,1),(2,1)(1,3) \)

To determine which relation is a function, we must remember that a function maps each input (or x-value) to exactly one output (or y-value). If an x-value is repeated with different y-values, it is not a function! Let's check the options: - A: The x-value 2 appears with different y-values — not a function! - B: The x-value 2 appears with different outputs as well — not a function! - C: The x-value 2 appears as both -3 and 3 — not a function! - D: The x-value 1 appears with different outputs (0, 1, 3) — not a function! None of these options represent a function, which makes it a bit of a tricky puzzle, doesn't it? Functions are like having a trusty sidekick; each input should only lead you down one path!