Answer the following question according to formal grammatical rules.

Which of the following sentences corrects the pronoun errors in this sentence?

If a person wants to help their community, they should research opportunities.

If a person wants to help their community, you should research opportunities.
If you want to help your community, a person should research opportunities.
If people want to help their community, they should research opportunities.
If a person wants to help it, they should research opportunities.