The following commands are executed using a stack: push(4) push(9) push(11) print(pop()) push(2) print(pop()) print(pop()) What would be the output?
a. 11, 9, 4, 2
b. 4, 9, 11, 2
c. 11, 9, 2, 4
d. 2, 11, 9, 4