Final answer:
Titan, the largest moon of Saturn, has a thick atmosphere comprised predominantly of nitrogen, along with methane. So, the correct answer is option B) Titan.
Step-by-step explanation:
The moon with a thick atmosphere made mostly of nitrogen is option B) Titan, which orbits Saturn. Titan is unique among moons in the solar system because of its substantial atmosphere that contains a majority of nitrogen, along with approximately 5% methane. This atmosphere is thicker than Earth's and is the only substantial one found on a moon.
Titan's atmosphere and surface conditions, including the presence of organic chemistry with complex molecules like tholins and surface features sculpted by liquid hydrocarbons, such as methane and ethane, make it an intriguing subject for scientific study.
The sun's UV light plays a role in creating these tholins in Titan's upper atmosphere, leading to an orange haze around the moon. Lakes and rivers of liquid hydrocarbons on Titan's surface have been confirmed through the imagery of the Cassini-Huygens mission, which showed landscapes with boulders made of water ice frozen harder than rock.