Error spotting (redundancy with 'reason why'): Choose the erroneous part (A/B/C) — mark D if correct — 'The reason why / he was rejected / was because he was too young. / No error.' Identify tautology and supply the idiomatic alternative.

Given data

• A. The reason why
• B. he was rejected
• C. was because he was too young.
• D. No error.

Concept/Approach (tautology)'Reason' already conveys 'because'. The structure 'reason … was because …' is redundant. Use 'The reason … was that …' or drop 'reason' and use 'because …'.

Step-by-step correction1) Keep 'reason': 'The reason why he was rejected was that he was too young.'2) Or remove 'reason': 'He was rejected because he was too young.'

Common pitfallsStacking 'reason' + 'because'; mixing complements after 'was'.

Final AnswerC — Replace 'was because' with 'was that'.