Concept:Identify the grammatically and contextually correct sentence from the given options.
Explanation:Check each option for errors.
Option A: "She walked twelve miles which are really a great distance..." - The phrase "twelve miles" is treated as a single unit of distance, so the verb should be singular "is" instead of "are". Hence, A is incorrect.
Option B: "The information presented ... indicate that ..." - The subject "information" is singular, requiring the singular verb "indicates" instead of "indicate". Hence, B is incorrect.
Option C: "He was promoted ... and received a free gift ..." - The word "gift" already implies something given without payment, so "free" is redundant. Hence, C is incorrect.
Option D: "Knowledge of at least four languages is required to pass the examination." - This sentence has no grammatical or contextual error. The singular subject "knowledge" correctly matches the singular verb "is". The meaning is clear and correct. Hence, D is correct.
Since only D is correct, option E ("All are correct") is false.
Answer:Option D (sentence D).