Question

Liquid ________ is used in rocket fuels.

• A. nitrogen.
• B. oxygen
• C. hydrogen
• D. both B and C

Answer 1

The correct option is D both B and C

Hydrogen a light and extremely powerful rocket propellant has the lowest molecular weight of any known substance and burns with extreme intensity (5,500°F). In combination with an oxidizer such as liquid oxygen, liquid hydrogen yields the highest specific impulse, or efficiency in relation to the amount of propellant consumed, of any known rocket propellant.

So, option D is correct.