Which taxpayer(s) will be required to file a 2021 federal income tax return? None of the individuals are blind.

a) Connie (70) and Gerald (68) are married and have gross income of $27,150. They lived together all year and will file a joint return.

b) Derrick (69) and Linda (62) are married and have gross income of $26,100. They lived together all year and will file a joint return.

c) Phoebe (68) has gross income of $19,500. She will file as head of household.

d) Sean (58) has gross income of $18,950. He will file as head of household