Final Answer:
The husband, age 80, with a gross income of $4,600, is not required to file a federal income tax return.
Step-by-step explanation:
In the United States, the requirement to file a federal income tax return depends on factors such as age, filing status, and income.
For the tax year 2022, individuals aged 65 or older have a higher income threshold before they are required to file. In this case, the husband, being 80 years old, falls into this category.
As of my last knowledge update in January 2022, for individuals aged 65 and older, the gross income threshold was $14,250 for singles and $27,000 for married couples filing jointly.
Since the husband's gross income is $4,600, which is below these thresholds, he is not obligated to file a federal income tax return.
It's important to note that tax laws and thresholds may change, so it's advisable to check the most recent IRS guidelines.
Additionally, the choice of filing separately by a married couple can have implications on tax liability, deductions, and credits.
However, in this specific scenario, the primary consideration for the husband not being required to file is his age and the relatively low gross income compared to the applicable threshold.