Which of the following countries is well known for having blocked the social networking site Facebook at the national level through strict internet control policies?

Introduction / Context:
Social media platforms such as Facebook play an important role in communication, business and politics. However, some countries exercise tight control over internet access and either block or severely restrict major platforms. General knowledge questions often ask about countries that maintain strong internet censorship, and Facebook is one of the most recognisable examples in this context.

Given Data / Assumptions:
- The question refers to a country that has banned or blocked Facebook at the national level.
- The options include China, Bhutan, Nepal, Pakistan and Iran.
- We assume the question refers to long term, system wide blocking rather than a short, temporary interruption.

Concept / Approach:
The key concept is internet censorship by governments. Some states maintain a national firewall that filters or blocks foreign websites. China is widely known for operating a system popularly called the Great Firewall, which restricts access to platforms such as Facebook, Twitter and Google services. Recognising this association makes the question straightforward if you are familiar with world affairs and technology news.

Step-by-Step Solution:
Step 1: Recall which countries are famous for very strict control over foreign social media platforms. Step 2: Note that China maintains comprehensive internet filtering that blocks Facebook and many other global platforms. Step 3: Consider Bhutan and Nepal. Both are small neighbouring countries of India and do not have a reputation for systematic blocking of Facebook for the entire population. Step 4: Think about Pakistan and Iran. These countries have occasionally imposed temporary bans or restrictions, but the longest running and most widely known national level block on Facebook is associated with China. Step 5: Based on this comparison, select China as the correct answer.

Verification / Alternative check:
News reports and technology coverage consistently mention that Facebook has been inaccessible in mainland China for many years because of government policy. Most users there rely on domestic alternatives such as WeChat and other local platforms. In contrast, residents of Bhutan, Nepal and Pakistan generally have access to Facebook, except for short lived blockages in specific circumstances, which confirms that China is the most accurate answer.

Why Other Options Are Wrong:
Bhutan: This country does not impose a long term nationwide ban on Facebook and is not known for severe internet censorship.
Nepal: Facebook is widely used in Nepal and the country does not maintain a permanent ban.
Pakistan: Authorities have at times restricted some platforms, but there is no continuous, permanent national level blocking comparable to China.
Iran: While Iran has restricted various platforms, the question typically refers to the most famous and widely cited example, which is China with its Great Firewall.

Common Pitfalls:
A common mistake is to think that every country with occasional internet restrictions fully bans Facebook. Another pitfall is mixing short term political decisions with long term policy. Candidates may also incorrectly assume that any country with internal conflict restricts all major websites. Focusing on the widely known and long standing example of systematic blocking helps avoid these errors.

Final Answer:
The country well known for having blocked Facebook nationwide through strict internet control policies is China.