Final answer:
The Sans-culottes were the group of radicals without knee breeches notable during the French Revolution, known for their significant influence on the political landscape and their support for the Jacobin club. The correct answer is option B.
Step-by-step explanation:
The group of radicals without knee breeches was called the Sans-culottes. This term refers to the poorer members of the Third Estate in France, mainly city laborers and workers, who played a significant role in the French Revolution. They could not afford culottes, the knee-length breeches worn by the more affluent classes, and their attire was emblematic of their radical political leanings. The Sans-culottes became an influential force, pushing for more democracy and social and economic reforms. They often supported the radical Jacobin club, which advocated for the abolition of the monarchy and the establishment of a republic.