Her professional activity code is 541310. Her major clients are real estate developers (both residential and commercial) for whom she prepares structural designs and construction plans. She also advises on building code requirements regarding the renovation and remodeling of existing structures. Mari collected $52,000 in consulting fees during 2013. This total includes a $3,000 payment for work she performed in 2012 and does not include $5,000 she billed in December for work performed in late 2013. In addition, Mari has an unpaid invoice for $6,000 from a client for work done in 2011. This client was convicted of arson in August 2013 and is now serving a five-year sentence in state prison. Mari feels certain that she will never collect the $6,000 she is owed. ?Mari does her work at the client?s premises or in her office at home (see item 5 below). Her business expenses for 2013 are as follows: ?