Fernando is a retired auto mechanic. Since retiring four years ago, he has made stained glass windows. Because he has only occasional sales, Fernando treats this activity as a hobby. A friend of Fernando's recommends him to a local merchant who is renovating her office and needs someone to make and install 15 new windows. The job takes Fernando a month to complete, and he is paid $3,000. In preparing his tax return, Fernando is unsure whether the $3,000 is subject to self-employment tax. The instructions accompanying his federal income tax return indicate that a payment is subject to self-employment tax only if an individual is engaged in a trade or business. Write a letter to Fernando explaining whether he is engaged in a trade or a business.