Assuming That Ammonia Serves as the Source of Both Nitrogen

Assuming that ammonia serves as the source of both nitrogen atoms of urea and that all cycles involved in the production of urea make one full turn, how many ATP equivalents and how many NADH are required to produce one molecule of urea?

A) 3 ATP equivalents, 1 NADH
B) 3 ATP equivalents, 0 NADH
C) 4 ATP equivalents, 1 NADH
D) 4 ATP equivalents, 0 NADH
E) none of the above