The example of how Radical Republicans sought to achieve their goals from the options given is:
2. working to ratify the fourteenth amendment.
The Fourteenth Amendment, ratified in 1868, was crucial for the Radical Republicans' efforts as it granted citizenship to all persons born or naturalized in the United States, including former slaves, and provided equal protection under the law. It was a key step in undermining the power of wealthy planters and ensuring rights for freedmen, including their right to vote, thus aligning with the Radical Republicans' objectives.
Option 1 does not directly relate to their goals of breaking planter power and securing voting rights, and option 3, while relevant, isn't a specific action taken in legislative reform like the ratification of the Fourteenth Amendment.