Explanation:

- Mesons are subatomic particles made of one quark and one antiquark.

- They are part of the hadron family like protons and neutrons.

- Option 1: Positive charge

- Some mesons carry a positive charge, like the positively charged pion (p?).

- Option 2: Negative charge

- Some mesons carry a negative charge, like the negatively charged pion (p?).

- Option 3: No charge

- Some mesons are neutral, carrying no charge, such as the neutral pion (p°).

- Option 4: Either charge

- Mesons can have positive, negative, or no charge.

Option 4: Either charge is correct.

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