The Sahara desert is the largest hot desert in the world, covering an area of approximately 3,600,000 square miles. It is located in the northern part of Africa and covers several countries.

The correct answer to the question is option B, which is 11 countries. Below is a detailed explanation of the countries that the Sahara desert touches:

1. Algeria: The Sahara desert covers 80% of Algeria's total land area, making it the largest country in the Sahara.

2. Chad: The Sahara desert covers the northern part of Chad, which is about 50% of the country's total land area.

3. Egypt: The desert covers the eastern part of Egypt, including the Sinai Peninsula.

4. Libya: The Sahara desert covers about 90% of Libya's total land area.

5. Mali: The Sahara desert covers the northern part of Mali, which is about 65% of the country's total land area.

6. Mauritania: The Sahara desert covers about 75% of Mauritania's total land area.

7. Morocco: The Sahara desert covers the southern part of Morocco.

8. Niger: The Sahara desert covers about 80% of Niger's total land area.

9. Sudan: The Sahara desert covers the northern part of Sudan, which is about 30% of the country's total land area.

10. Tunisia: The Sahara desert covers about 40% of Tunisia's total land area.

11. Western Sahara: The Sahara desert covers the majority of Western Sahara, which is a disputed territory between Morocco and the Polisario Front.

Therefore, the Sahara desert touches 11 countries in Africa.