The audience whistled and shouted ,waiting for her to sing one ___song.

问题描述:

The audience whistled and shouted ,waiting for her to sing one ___song.
A.last B.final C.ending D.concluding

"MORE" should be the best answer but it's not here.
so I pick A,you can say "one last song/dance",never heard of "one ending song" or "one concluding" song",they should be used with "THE",I think "final" should be used with "THE" too.
What if I want her to sing more than just one extra song?