Error spotting (collocation with 'prejudicial'): Identify the erroneous segment (A/B/C) — choose D if there is no error — 'It is easy to see that / a lawyer's demeanour in court / may be prejudicial against the interests of his client. / No error.' Ensure correct preposition after 'prejudicial' and keep the legal-English phrasing tidy.

Given data & concept
In legal and formal English, the adjective 'prejudicial' takes the preposition to, not 'against': 'prejudicial to someone's interests'.

Step-by-step correction
(C) 'prejudicial against' → 'prejudicial to the interests of his client'.Corrected sentence: 'It is easy to see that a lawyer's demeanour in court may be prejudicial to the interests of his client.'

Common pitfalls
Using 'against' after adjectives that collocate with 'to' (akin to, detrimental to, prejudicial to).

Final Answer
(C) is erroneous → write 'prejudicial to the interests of his client'.