The correct option is C X - Sanctuary, Y - National Park, Z - Biosphere Reserve
X - Sanctuary, Y - National Park, Z - Biosphere Reserve.
Areas meant for the conservation of both plants and animals and in which little human activities like collection of timber are allowed are known as a biosphere reserves. Hence, Z is a biosphere reserve.
Areas involved in the protection of both flora and fauna but in which no human activities are allowed are known as national parks.
Areas meant only for conservation of fauna are known as sanctuaries.