Answer: Proton
Step-by-step explanation:
In an atom there exist three types of sub atomic particles
1) Electrons
2) Neutrons
3) Protons
so we know that electrons are negatively charged particles which stays in a finite orbit as per their energy level
Protons are positively charged particles which remains inside the nucleus and they are tightly bound inside it
Neutrons are neutral sub atomic particles which do not have any charge in it.
So we have correct answer as
D) Proton