Final answer:
The person in question who was a prominent figure in numerous professions and a strong advocate for conservation, establishing many national parks and forests, is Theodore Roosevelt.
Step-by-step explanation:
The individual described as a New York City police commissioner, writer, Dakota cattle rancher, Assistant Secretary of the Navy, Rough Rider, big game hunter, and U.S. president, and a champion of the conservation movement, is c) Theodore Roosevelt. Roosevelt's vast contributions to conservation include establishing numerous national parks, national forests, and national monuments. He was indeed a member of the Boone and Crockett Club and was known for his vigorous outdoor lifestyle. His engagement with the natural environment and his passion for hunting influenced his policies on conservation, leading to the creation of state agencies to regulate hunting and the establishment of wildlife refuges to protect wilderness and species for future enjoyment.
During his presidency, Roosevelt saw the addition of vast areas to the national forests in the West and set aside lands for public use, ensuring the conservation of America's natural resources for future generations. His time spent in the wilderness and his friendship with naturalists like John Muir had a significant impact on these policies. Throughout his political career, from his police commissioner role to the presidency, Roosevelt's experiences and personal convictions greatly influenced his approach to environmental conservation and the expansion of federal power to protect public lands.