The Soviet Union’s series of probes that landed on Venus was called the Venera program. “Venera” is the Russian name for Venus, so the mission title literally identifies the planetary target.
The program ran from 1961 to 1984 and included orbiters, atmospheric probes, flyby spacecraft, and landers. Venus’s crushing pressure, intense heat, and corrosive cloud layers made every landing technically demanding. Even successful landers survived only briefly, typically from a few minutes to around two hours.
Venera missions established several major milestones. Venera 3 became the first human-made object to reach the surface of another planet in 1966, although it stopped transmitting before impact. Venera 7 made the first successful soft landing on another planet and transmitted data from the surface in 1970. Venera 9 later returned the first photographs taken on the surface of another planet.
The wrong choices are understandable because Luna was the Soviet lunar program, Mars refers to missions aimed at Mars, and Vega was a later Soviet mission series that included Venus atmospheric balloons while also targeting Halley’s Comet.