Linda received $90,000 in salary income for 2016. She has no dependents. Determine her income tax liability

Question:

Linda received $90,000 in salary income for 2016. She has no dependents. Determine her income tax liability under each of the following independent situations:
a. She files as a single individual.
b. She is married and files a joint return with her spouse. Their only income is her $90,000 salary.
c. She is married but files a separate return.