(C) Nitrogen
(A) Hydrogen
(B) Carbon dioxide
(D) None of these
🧠 Explanation:
- Hydrogen is a highly combustible gas that burns with a pale blue, almost invisible flame in air.
- It reacts explosively with oxygen, making it suitable for use as a rocket fuel.
- In contrast, Carbon dioxide and Nitrogen are non-combustible and are actually used to suppress fires.
- Therefore, the correct answer is (A) Hydrogen.
