Which mission was responsible for putting the first rover on another planet?

The mission responsible for putting the first rover on another planet is indeed the Pathfinder mission. Launched by NASA in 1996, Mars Pathfinder successfully landed on Mars in July 1997 and deployed the Sojourner rover, marking a significant milestone in planetary exploration. This mission showcased not just the landing of a spacecraft on another planet, but it also involved the deployment of a mobile robotic rover that could traverse the Martian surface, analyze rocks, and send data back to Earth.

The other missions listed do not pertain to rovers on planets. Galileo was focused on studying Jupiter and its moons, Cassini was an important mission to Saturn, and Giotto was designed to study Comet Halley. These missions were groundbreaking in their own right but did not involve the deployment of rovers on planetary surfaces like Mars Pathfinder did. The successful operation of the Sojourner rover provided invaluable information about Mars and laid the groundwork for future rover missions.