In order for nuclear fusion to occur, the core of the sun must be hot enough to overcome the of the nuclei. select one: a. electromagnetic repulsions b. solar wind c. gravitational tides d. strong nuclear forces e. doppler effect

The answer is option a, that is " electromagnetic repulsions".
The sun generates energy by nuclear fusion, and converts a part of its mass into energy and nuclear fusion is the source of all energy that is released by the sun. The two things which are required for the process of nuclear fusion are high temperature and the high densities.

They are all full and don't need any more electrons in there outer shell.

Matter- occupies space and possesses rest massno matter is the opposite