What subatomic particle carries a positive charge and is found in the nucleus of an atom?

The subatomic particle that carries a positive charge and is located in the nucleus of an atom is the proton. Protons play a crucial role in defining the identity of an element. The number of protons in the nucleus determines the atomic number, which is unique to each element on the periodic table. For example, an atom with one proton is hydrogen, while an atom with six protons is carbon.

In contrast, neutrons, which are also found in the nucleus, do not carry any charge; they are neutral. Electrons, on the other hand, carry a negative charge and orbit around the nucleus in various energy levels. An "atom" refers to the basic unit of matter composed of protons, neutrons, and electrons, but it does not identify a specific subatomic particle. Hence, the only correct answer that specifies a positively charged particle in the nucleus is the proton.