For Java Class:

Suppose stacks are implemented with a linear linked list that has just one private instance variable, firstNode, which refers to the first element of the list. Assume that firstNode points to the top of the stack. What is the run time of (1) push and (2) pop in this implementation? A. (1) O(1) B.(1) O(1) C. (1) On) D. (1) On) E. (1) O(log2 n) (2) O(1) (2) O(n) (2) O(1) (2) On) (2) O(1)