How can scientists be certain that nuclear fusion is not occurring on the outer gas giants? A. These planets are not rocky
B. These planets do not contain enough gases to produce energy
C. These planets are too large to produce energy
D. These planets do not produce energy,

D. These planets do not produce energy,

Explanation:

Nuclear fusion leads to the production of energy and when energy is produced on a planetary scale, it radiates. Scientists have not picked up any energy coming from the gas giants which means that they do not produce energy which gives us proof that there is no nuclear fusion occurring on them.

A planet being rocky is not a prerequisite for nuclear fusion to occur which rules out the first option. The sun has more gas volume than these gas giants yet produces energy so the second option is wrong as well. The third option is also incorrect because the sun is many times larger than the gas giants yet initiates nuclear fusion.  

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