A bag has 4 balls: 1 red (R), 1 green (G), 1 yellow (Y), and 1 orange (O).

Answer:
D {R,G,Y,O}
Step-by-step explanation:
If there are 4 balls 1 red (R), 1 green (G), 1 yellow (Y), and 1 orange (O).
We must choose one of the balls. The sample space is what our available choices are
{R,G,Y,O}