Answer:
The second set is a function as none of the x values repeat.
Explanation:
In order for a set of ordered pairs to be a function, they must only have one range value for each domain value.
In other words, an x value cannot occur twice.
Within the first set, the value x=2 is repeated 5 times. This means that it is not a function
Within the third set, the value x=1 is repeated twice and x=4 is repeated twice, This means that it is not a function
Within the fourth set, the value x=1 is repeated twice and x=2 is repeated twice, this means that this is not a function
The second set is a function as none of the x values repeat.