For the following problems, assume the taxable year is 2022. Determine Lilly’s 2022 filing status in each of the following independent cases:

a. Lilly and Paul have been living together since 2020. They were married on December 13, 2022.

b. Lilly married Paul in 2015. They were divorced on November 8, 2022, and have no dependent children.

c. Lilly married Paul in 2015. They separated in 2021 and have not lived together since, but they have not divorced.

d. Lilly divorced Paul in 2021. Lilly’s grandparent is considered a dependent and lives with Lilly.