If the "Fuel" for Nuclear Fusion Is Nuclei of Hydrogen

Multiple Choice

If the "fuel" for nuclear fusion is nuclei of hydrogen, and the Earth's oceans are filled with hydrogen atoms in water all being jostled together, why isn't there a lot of fusion happening in our oceans?

A) the hydrogen in our oceans is the wrong type of hydrogen for fusion
B) for hydrogen nuclei to fuse, they must get very close to each other, which the nuclei in the oceans cannot do
C) for hydrogen to fuse, the nuclei must first join together in long chains of atoms
D) on Earth, only hydrogen that is in deep mines under the Earth is far enough underground for fusion
E) you can't fool me, hydrogen in the Earth's oceans does undergo fusion; that's what keeps our oceans warm