Oscar is a resident of Country B. Country B does not have a tax treaty with the USA. Oscar is an employee of a private company in country B and his employer sends him to the USA in order to do certain work needed to be done in the USA.
Here are his days of presence in the US:
• September 1, 2018, until April 15, 2019. During this time he made $200,000.
• January 1, 2019 until June 30, 2020. During this time he made $55,000.
• He does not return to the USA after this time.
Other facts:
• During each of 2018-2020 he had $155,000 of country B source interest income (would be subjected to the ordinary income tax rate here in the US if taxed here).
• The tax rates in country B are lower than of the USA by a substantial amount.
• The amounts earned that are US source earnings will not be taxed in country B at the same time.

a. Describe his tax status here in the USA and what taxes he would have to pay here. I am not interested in the computation of tax, but what income is subjected to US tax and what type of US taxes he would be subjected to on that income.

b. Assume that country B does have a tax treaty with the US that uses the terms of the 2016 US Model tax treaty. Discuss how this changes things.