Final answer:
B) Ethan Allen was the leader of the Green Mountain Boys, a militia critical during the American Revolutionary War, notably taking Fort Ticonderoga in 1775.
Step-by-step explanation:
The leader of the Green Mountain Boys was b) Ethan Allen.
They were a militia organization first established in the late 1760s in the territory between the British provinces of New York and New Hampshire, known as the New Hampshire Grants.
Under Ethan Allen's leadership, the Green Mountain Boys played a crucial role during the early stages of the American Revolutionary War, including the capture of Fort Ticonderoga in May 1775.