Chemical reaction, generally speaking. It's a vague definition, but it's easy to remember.
Answer:
D. is the Answer. ✅
Explanation:
The Moon is 1/4 the size of Earth.
A is not right because Moon isn't a dwarf planet.❌
B is not right because the Moon isn't 1/2 the size of Earth.❌
C is not right because the Moon is no where near as large as Earth.❌
Protons = 20
Electron = 20
Neutrons = 20
Hope this Helps :)