Which sentence does not contain any punctuation errors?
a. what time, lieutenant, must we report for duty?
b. what time lieutenant, must we report for duty?
c. what time, lieutenant must we report for duty?
d. what time lieutenant must we report for duty?

Aman lives on the twelfth floor of an apartment building. every morning he takes the elevator down to the lobby and leaves the building. in the evening, he gets into the elevator, and, if there is someone else in the elevator -- or if it was raining that day -- he goes back to his floor directly. otherwise, he goes to the tenth floor and walks up two flights of stairs to his apartment.