Answer:
Top left: not a function
Top right: not a function
Bottom left: function
Bottom right: not a function
Explanation:
A function is a relationship where each x value has it's own y value ( note that domain = x values and range = y values)
For the one on the top left.
S and n have more than one y value.
Because s and n have more than one y value the relation is not a function
For the one of the top right.
There x value "c" has multiple y values therefore the relation is not a function
For the one on the bottom left
Each x value has it's own y value therefore it is a function ( note that the y values can repeat. It's only the x values that can't repeat. )
For the one on the bottom right
The x value "-5" has multiple y values therefore the relation is not a function