Martha and Marty Mertens are married and file a joint return. Marty started his own business at the beginning of the current tax year and reported...

Martha and Marty Mertens are married and file a joint return. Marty started his own business at the beginning of the current tax year and reported net income of $14,000 for the year. Martha worked full time as a waitress earning $8,000, excluding tips of $3,000. Marty and Martha maintained a home for their 11-year-old son. What is their earned income credit for 2018?