Mr. Lamb did not have curtains in his house because he wanted visitors in his house. This option suggests that Mr. Lamb intentionally chose not to have curtains for a specific reason related to his desire to have visitors in his house. Let's delve deeper into this answer.

Reasoning:
- The absence of curtains can create an open, welcoming atmosphere in a house.
- Curtains can sometimes create a barrier between the inside and outside of a house, making it less inviting for visitors.
- Mr. Lamb may have preferred to have an open and inviting space for his guests to feel comfortable and welcome.

Explanation:
1. Open and welcoming atmosphere:
- By not having curtains, Mr. Lamb's house would have an open and airy feel, allowing natural light to fill the rooms.
- This can create a warm and inviting atmosphere, making visitors feel more comfortable and at ease.

2. Absence of barriers:
- Curtains can act as physical barriers between the inside and outside of a house.
- Mr. Lamb may have wanted to eliminate such barriers to encourage visitors to feel welcome and freely enter his house.

3. Promoting social interactions:
- Without curtains, Mr. Lamb's house would have a more open layout, enabling easier social interactions between visitors and residents.
- This can facilitate conversations and connections, enhancing the overall experience for both Mr. Lamb and his guests.

4. Creating a sense of transparency:
- Not having curtains can symbolize transparency and honesty.
- Mr. Lamb may have wanted to convey a sense of openness and authenticity to his visitors.

In conclusion, Mr. Lamb did not have curtains in his house because he wanted visitors in his house. This choice suggests his intention to create an open, welcoming environment for social interactions and to promote transparency and authenticity.