Which relation is a function? (A) \( (1,0),(3,0),(1,1),(3,1)(1,3) \)

To determine whether a relation is a function, we must verify that **each input** (the first element of each ordered pair) is associated with **exactly one output** (the second element of each ordered pair). Let's examine the given relation: \[ (1,0),\ (3,0),\ (1,1),\ (3,1),\ (1,3) \] - **Input 1** is associated with three different outputs: **0**, **1**, and **3**. - **Input 3** is associated with two different outputs: **0** and **1**. Since **input 1** and **input 3** each map to multiple outputs, this violates the definition of a function, where each input must map to **exactly one output**. **Conclusion:** The given relation **is not** a function because some inputs are associated with multiple outputs. Answer: **A) is not a function because some inputs are paired with multiple outputs.**