Which Indian national leader is popularly known as the Iron Man of India?

Introduction / Context:
Many Indian freedom fighters and leaders are known by distinctive titles that capture their character and contribution. Remembering these titles helps candidates quickly answer history and polity questions in competitive exams. The title Iron Man of India is associated with a leader who played a crucial role in unifying the country after independence.

Given Data / Assumptions:
- The title provided is Iron Man of India.- The options include several prominent leaders of the national movement and early post independence period.- We assume standard Indian history accounts of these leaders contributions.

Concept / Approach:
The title Iron Man symbolises firmness, strong will and unyielding determination. Among the leaders listed, Sardar Vallabhbhai Patel is consistently described as the Iron Man because of his tough stance in integrating princely states into the Indian Union and his decisive administrative style. Connecting each leader with his famous sobriquet is the key to selecting the right option.

Step-by-Step Solution:
- Step 1: Recall that Sardar Vallabhbhai Patel was the first Deputy Prime Minister and Home Minister of independent India.- Step 2: He is credited with integrating over five hundred princely states into the Indian Union, often through firm negotiation.- Step 3: Because of this toughness and strong will, he came to be popularly known as the Iron Man of India.- Step 4: Compare this association with the other options who have different titles.- Step 5: Conclude that Sardar Vallabhbhai Patel is the correct answer.

Verification / Alternative check:
An alternative confirmation is to recall common textbook statements such as Patel being the architect of modern India or that his statue, the Statue of Unity, symbolises the Iron Man. Mahatma Gandhi is called Father of the Nation, Jawaharlal Nehru is known as Chacha Nehru and Subhas Chandra Bose is linked with Netaji. These different titles make it easier to verify that Iron Man of India points to Sardar Vallabhbhai Patel.

Why Other Options Are Wrong:
Bhagat Singh is a revolutionary martyr revered for courage but is not known by the Iron Man title.Mahatma Gandhi is associated with titles like Mahatma and Father of the Nation, linked to non violence and moral leadership.Jawaharlal Nehru is remembered as the first Prime Minister and is popularly called Chacha Nehru by children.Subhas Chandra Bose is honoured as Netaji, reflecting leadership of the Indian National Army, not the Iron Man image.

Common Pitfalls:
Some candidates confuse the Iron Man title with similar sounding nicknames like Lion of Punjab used for Lala Lajpat Rai. Another mistake is to select Bhagat Singh due to his strong revolutionary image. Careful memorisation of leader title pairs and periodic revision can help avoid such confusion in exam conditions.

Final Answer:
The leader popularly known as the Iron Man of India is Sardar Vallabhbhai Patel.