In an experiment to learn whether substance M can help restore memory, the brains of 20 rats were treated to damage their memories. First, the rats were trained to run a maze. After a day, 10 rats (determined at random) were given substance M and 7 of them succeeded in the maze. Only 2 of the 10 control rats were successful. The two-sample z test for the difference in the true proportions

a. Gives z = 2.25, P < 0.02.

b. Gives z = 2.60, P < 0.005.

c. Gives z = 2.25, P < 0.04 but not < 0.02.

d. Should not be used because the Random condition is violated.

e. Should not be used because the Large Counts condition is violated.

Select the best answer.