Final answer:
Sue does not have gross income in this scenario because the $10,000 found inside the used piano is not considered income.
Step-by-step explanation:
No, Sue does not have gross income in this scenario. Gross income refers to the total income received by an individual before deductions or expenses. In this case, the $10,000 found inside the used piano is not considered income because Sue did not earn it or receive it as payment for goods or services. It is considered a windfall or unexpected gain, which is not included in gross income.