In April 2022, Dan is audited by the IRS for the year 2020. During the course of the audit, the agent discovers that Dan’s deductions for business travel are unsubstantiated and a $600 deficiency assessment is proposed for the tax year 2020. The agent also examined some prior year returns. The agent discovers that Dan failed to report $40,000 of gross business income on his 2018 return. His gross income in 2020 was $60,000. The agent also discovers that Dan failed to file a tax return in 2013. Will the statute of limitations prevent the IRS from issuing a deficiency assessment for 2020, 2018, or 2013?