Which among the given choices is taxable for his/her 2021 income in earned in Canada (not worldwide):

a.

John, a member of the Canadian Armed forces, was assigned for work in Ukraine for a year, starting January 1, 2021.

b.

Mary, a US citizen, arrived in Canada for work starting March 1, 2021, until the end of the year.

c.

Chloe, a resident of Canada who works in Alberta in 2021.

d.

Elias, a US citizen, arrived in Canada for work starting August 1, 2021, until the end of the year.