Error spotting — Identify the erroneous segment (A/B/C) or mark D if correct: 'Since India has gained Independence / 49 years ago. / much progress has been made in almost every field. / No error.' Check incompatibility of 'since' with 'ago' and tense alignment for time references.

Concept/Approach (time markers)
'Since' (as a time conjunction meaning 'from the time when') does not co-occur with 'ago'. Use simple past with a time adverbial '… years ago': 'India gained Independence 49 years ago.' Or use 'since' with a point in time ('since 1947') and present perfect in the main clause.

Corrections
Option 1: 'Since India gained Independence, much progress has been made …' (drop 'ago').Option 2: 'India gained Independence 49 years ago; much progress has been made …' (no 'since').

Final Answer
A — The 'since has gained' frame with 'ago' is ungrammatical.