Explanation:

- The relationship between "Ocean" and "Sea" indicates a large entity and a smaller one within it. The ocean is a vast body of water, while a sea is a smaller part of the ocean.

- For "Happiness," we need a smaller, related concept that fits within the broader emotion of happiness.

- Option 4: Joy is a specific, intense feeling within the broader scope of happiness. It closely mirrors the relationship of Ocean to Sea.

- Option 1: Hopeful is a feeling of looking forward with optimism, related to future possibilities, not directly a part of happiness.

- Option 2: Prosperity relates to wealth and success, indirectly connected to happiness but not a direct sub-concept.

- Option 3: Peace refers to tranquility, which can exist independently from happiness.

.