1. The problem asks which of the given relations is a function. 2. A relation is a function if every input $x$ has exactly one output $y$. 3. Let's analyze each graph: - Top-left (sine-wave-like curve): For each $x$, there is exactly one $y$. This is a function. - Top-right (sideways parabola): For some $x$ values, there are two $y$ values. This is not a function. - Bottom-left (circle): For some $x$ values, there are two $y$ values. This is not a function. - Bottom-right (V-shaped graph): For each $x$, there is exactly one $y$. This is a function. 4. Therefore, the top-left and bottom-right graphs represent functions.