Identify the subatomic particles listed in the problem: neutrinos, neutrons, protons, and electrons.
Recall the basic properties of each subatomic particle: Neutrinos are neutral, neutrons are neutral, protons are positively charged, and electrons are negatively charged.
Focus on the charge of each particle: Neutrinos have no charge, neutrons have no charge, protons have a positive charge, and electrons have a negative charge.
Determine which particle has a positive charge based on the properties: Protons are the only subatomic particles with a positive charge.
Conclude that protons are the subatomic particles with a positive charge, as they are the only ones listed with this property.