The alpha-particle carries two positive charges. Its mass is very nearly equal to that of

An alpha particle is composed of two protons and two neutrons and is essentially the helium-4 nucleus (written 4He2+); in nature an alpha particle exists as the nucleus of a helium atom [2]. Because it is simply the helium nucleus missing the two bound electrons, its mass is very nearly that of a neutral helium atom — the only significant difference is the mass of the two electrons and the small nuclear binding (mass defect). Thus option 2 is correct. Options 1 and 4 ignore the two neutrons present in the alpha particle, and option 3 is incorrect because positrons (antielectrons) are not constituents of an alpha particle.

Sources

1. [1] https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/elementary-particle
2. [2] https://www.uomustansiriyah.edu.iq/media/lectures/6/6_2025_03_16!12_08_25_AM.pdf