**Answer:**

The correct answer is option 'D' - All of these.

**Explanation:**

The Hilsa fish is a popular fish known for its taste and texture, and it is often a topic of discussion among various groups of people. Let's discuss each of these groups in detail:

**Fishermen:**
Fishermen are directly involved in catching Hilsa fish from rivers, lakes, or the sea. They have extensive knowledge and experience in fishing and are well aware of the behaviors, habitats, and migration patterns of Hilsa fish. They often discuss Hilsa fish and share their experiences, techniques, and stories related to catching this prized fish.

**Countries:**
Hilsa fish is considered a delicacy in several countries, especially in South Asia. It holds cultural and economic significance in these regions. Countries like Bangladesh, India, Myanmar, and others have a significant Hilsa fish industry. They discuss Hilsa fish from various perspectives, including its conservation, trade, and cultural importance. Governments and policymakers often engage in discussions to manage the fishing industry and ensure sustainable practices to protect the Hilsa fish population.

**People:**
Hilsa fish is widely consumed and appreciated by people, and it often becomes a topic of conversation among food enthusiasts, chefs, and those who enjoy seafood. People discuss various aspects of Hilsa fish, including its taste, cooking methods, recipes, nutritional value, and its availability in different regions. They share their preferences, experiences, and recommendations related to Hilsa fish.

**Conclusion:**
Given these points, it can be concluded that all of the mentioned groups - fishermen, countries, and people - talk about Hilsa fish. The discussion may vary in terms of context, but the Hilsa fish is a subject of interest for all these groups.