Identifying Revenue Bonds

Consider the following scenarios where different types of bonds are issued:

1. A government issues a bond that is backed by specific revenues from a designated project, such as a toll road.

2. A corporation issues a bond that promises higher interest payments in times of financial distress, but lower payments in stable times.

3. A municipality issues a bond that offers tax-exempt interest income to investors, with proceeds allocated specifically for community development.

Based on the information above, which type of bond is characterized by its backing from specific revenue sources related to a project?