What relief can Karen request after filing a joint return with unreported income?

Karen can request Innocent Spouse Relief after filing a joint return with unreported income because this provision is designed to protect one spouse from liability for tax owed due to the other spouse's errors or omissions. When a couple files jointly, both individuals are generally held equally responsible for the tax liabilities that arise from that joint return. However, if one spouse can demonstrate that they were unaware of the unreported income and that it would be unfair to hold them liable for the tax associated with it, they may qualify for this relief.

Innocent Spouse Relief allows the innocent spouse to be relieved from additional tax owed due to the other spouse's unreported income, assuming they meet certain criteria established by the IRS. This option is particularly relevant in situations where one spouse may have had no knowledge of the income in question and can prove that they did not benefit from it.

The other choices do not provide the specific relief related to unreported income on a joint return in the same manner as Innocent Spouse Relief.