Comet Shoemaker-Levy 9 hit the planet

Comet Shoemaker–Levy 9 struck the planet Jupiter in mid‑July 1994, when a train of more than twenty fragments impacted Jupiter’s atmosphere over several days, producing bright fireballs and dark scars visible even with modest telescopes. The collisions provided a unique, directly observed example of a planetary impact and yielded important data on Jupiter’s atmospheric composition and response to large impactors. Jupiter’s status as the largest gas giant, with a deep, dynamic atmosphere and strong gravity, explains both why the comet was captured and why the impacts produced such prominent atmospheric features [1]. Thus the correct answer is Jupiter.

Sources

1. [1] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 2: The Earth's Crust > The Solar System > p. 3