Explanation:
Discrete data can only have certain values. For example, if you roll a die, there are only 6 numbers you can get. Continuous data can have any value within a range.
Graphically, discrete data will appear as only points, where as continuous data appears as a line or curve.
So the top left and bottom right graphs are discrete. The top right and bottom left graphs are continuous.
To be a function, each x value can only have 1 y value. Graphically, we can check this using the "vertical line method". Imagine a vertical line (or use a ruler or straight edge) and move it from left to right. If it ever crosses the graph in two or more places, the graph is not a function.
Therefore, the graphs on the left are not functions, and the graphs on the right are functions.