M. Sham Lal was an eminent Indian intellectual who did most of his commendable work in which of the following fields?

Introduction / Context:
M. Sham Lal (often written as Sham Lal) was a prominent Indian intellectual, best known for his long association with newspapers and for shaping literary and cultural criticism in India. This question tests recognition of his main professional field, which often appears in competitive exams under famous personalities and their contributions to public life and letters.

Given Data / Assumptions:

• The person in question is M. Sham Lal.
• He is said to have done commendable work.
• We must identify the field where his contribution is most noted.
• Options include social service, trade unionism, journalism, politics and banking.

Concept / Approach:
The concept here is matching personalities with domains. Sham Lal was associated for many years with major newspapers, including roles as editor and as a leading literary critic. His columns and essays explored literature, philosophy and culture. That profile clearly belongs to the field of journalism, especially editorial and opinion writing, rather than social work, politics or trade union leadership.

Step-by-Step Solution:
Step 1: Recall that Sham Lal was closely connected with major English-language newspapers in India. Step 2: Remember that he served as an editor and later as a columnist writing on books, culture and ideas. Step 3: Compare this background with each option. Editing newspapers and writing columns fit squarely under journalism. Step 4: Note that there is no famous record of him as a trade union leader, frontline politician, professional social worker or banker. Step 5: Conclude that Journalism is the correct choice.

Verification / Alternative check:
If you have seen references to Sham Lal in exam guides or newspapers, he is usually described as an editor and critic rather than as a mass-movement activist. Obituaries and tributes highlight his role in shaping editorial pages and literary discourse, further confirming that his primary contribution was in print media and commentary, which fall under journalism.

Why Other Options Are Wrong:
Trade unionism: While important in labour history, there is no widely known connection between Sham Lal and leading trade unions.
Social service: He may have indirectly influenced society through writing, but he is not famous as an NGO or grassroots social worker.
Electoral politics: Sham Lal did not achieve fame as an elected representative or party leader.
Banking: There is no notable association with the banking sector; his reputation does not come from finance or corporate leadership.

Common Pitfalls:
Some candidates assume that anyone called an eminent intellectual must be a political leader or social reformer. In India, however, a number of influential thinkers have worked primarily as editors, journalists and critics. The safest strategy is to remember a few core facts: Sham Lal is to journalism and literary criticism what some others are to politics or activism. Keeping such tags prevents confusion in MCQs.

Final Answer:
M. Sham Lal did his most commendable work in the field of Journalism.