Singer, a citizen and resident of country H, conducts a three-concert tour in the United States. A multi-talented individual, Singer sells tickets to his concert from the ticket booth before his concert begins. During intermission, he sells beverages from the concession stand. Afterwards, Singer sells t shirts at the concession stand.

Is Singer engaged in a U.S. trade or business? Explain.

If Singer is engaged in a U.S. trade or business, what income is subject to U.S. tax?

When does Singer pay any U.S. tax?