In which scenario does the married filing jointly status apply?

The married filing jointly status is applicable to married couples who live together and choose to combine their incomes on one tax return. This filing status allows the couple to benefit from potentially lower tax rates and access to various tax credits and deductions that may not be available when filing separately. When both spouses report their combined income, they may also qualify for higher income thresholds for certain tax credits and a bigger standard deduction compared to filing separately.

In contrast, married couples living apart who file separate returns would not utilize this filing status as they are not combining their incomes on one return. Additionally, individuals in common-law marriages or unmarried couples living together do not meet the requirements for the married filing jointly status, as that status is specifically reserved for legally married couples who file together. Therefore, B is the only scenario that correctly describes the application of the married filing jointly status.