Which of the following will help most in biosphere is the conservation of wildlife?

Making numerous sanctuaries will help most in biosphere in the conservation of wildlife.
A Wildlife Sanctuary is a protected area of importance for flora, fauna, or features of geological or other interest, which is reserved and managed for conservation and to provide opportunities for study or research. The Wild Life (Protection) Act, of 1972 provides for the establishment of Protected Areas in India.
Sanctuaries help in protection of endangered species of plants and animals in their natural environment.