Step 1: Understanding the Concept:
This question tests geographical knowledge of the administrative offices of prominent international conservation agencies.
Step 2: Detailed Explanation:
Let us examine the location of each respective agency:
1. IUCN (International Union for Conservation of Nature):
Established in 1948, the IUCN is the global authority on biodiversity conservation and ecological status assessments.
Its central headquarters is located in Gland, Switzerland (spelled "Glands" in some classical examinations).
2. UNEP (United Nations Environment Programme):
UNEP was founded following the UN Conference on the Human Environment (Stockholm Conference) in 1972.
Its global headquarters is situated in Nairobi, Kenya.
This is notable as it represents one of the few major global UN agencies based in a developing country.
Step 3: Final Answer:
The IUCN headquarters is located in Gland, Switzerland, and the UNEP headquarters is in Nairobi, Kenya.
This corresponds directly to Option (B).