Answer:
d.#include deque
Explanation:
We have to include deque library in order to use a deque container and the syntax to include is #include<deque>.Deque is a double ended queue which is a sequence container and allows operations of contraction and expansion on both ends of the queue.Double ended queues are a special case of simple queue since in simple queue the insertion is from rear end and deletion is from front end but in deque insertion and deletion is possible at both ends rear and front.
