Why is deleting in a single linked list O(1)?

Question

I do not quiet understand why deleting at the end of a single linked list goes in O(1) time, as the wikipedia article says.

A single linked list consists out of node

Answer 1

For future reference, I must say after some research I found that none of the arguments provided in response to this question are relevant. The answer is that we simply decide for the top of the stack to be the head of the linked list (rather than the tail). This will introduce a slight change into the push routine but then the pop and push will both remain o(1).