Which particles have a positive charge?

Alpha particles are indeed positively charged particles. An alpha particle consists of two protons and two neutrons, making it identical to a helium nucleus. The presence of the two protons is what gives the alpha particle its positive charge, as protons are the subatomic particles responsible for positive charge in atoms.

In contrast, gamma rays are a form of electromagnetic radiation and carry no charge. Beta particles can be either negatively charged (beta-minus, which are electrons) or positively charged (beta-plus, which are positrons), making it important to identify which type of beta particle is being referenced. Neutrons are neutral particles and carry no charge at all. Thus, among the options provided, alpha particles are the correct response as positively charged entities.