She chose the one involving stunts.
The film is directed by Nikhil Advani.
"Nikhil gave me choice and said one is going to be a emotional role and the other one is an action part. I said, of course, I want to do the action part," Huma said.
"I am really thankful that he thought I could do it. If you get a choice (of a role), anybody would feel good about it," he added.
Huma, seen in films like 'Gangs Of Wasseypur', 'Luv Shuv Tey Chicken Khurana' and 'Ek Thi Daayan', said it was fun to be training under Hollywood stunt experts Tom Struthers and John Street of 'Inception' and 'The Dark Knight Rises' fame.
"I didn't know anything. Then I learnt how to hold a gun, hand-to-hand combat, the jumps... the whole process of doing action together was fun," she said.
'D-Day' also features Rishi Kapoor, Arjun Rampal, Irrfan and Shruti Haasan.