When is the last day that federal income tax forms can be submitted?

The correct answer is April 15th because it has been established as the standard due date for individual federal income tax returns in the United States. This date may occasionally shift if it falls on a weekend or public holiday, in which case the deadline is usually extended to the next business day. Understanding this deadline is important for tax planning and compliance, as failing to submit tax forms by this date can result in penalties and interest on unpaid taxes. The other options do not reflect the established deadline, making April 15th the only accurate choice for the last day to submit federal income tax forms.