In the following sentence, identify the part that contains a grammatical error: "Her knowledge in English / gives her great advantage / over me."

Introduction / Context:
This question checks your understanding of preposition usage and natural English phrasing with the noun "knowledge". In standard English, we do not usually say "knowledge in a language"; instead, we say "knowledge of a language". Such subtle preposition errors are common in exams and must be corrected for accurate and fluent expression.

Given Data / Assumptions:
- The sentence is divided into parts:
A: "Her knowledge in English"
B: "gives her great advantage"
C: "over me."
- We must select the part containing the error.
- The intended meaning is that her command of the English language gives her an advantage compared to the speaker.

Concept / Approach:
The standard collocation is "knowledge of" when referring to a subject, field, or language, for example, "knowledge of mathematics", "knowledge of history", or "knowledge of English". Using "in" in this context is incorrect. Therefore, the phrase in part A should be "Her knowledge of English". The rest of the sentence is acceptable, although adding an article ("a great advantage") would make it even more natural, but the main tested error is the preposition.

Step-by-Step Solution:
Step 1: Read the full sentence: "Her knowledge in English gives her great advantage over me."
Step 2: Focus on the noun "knowledge" and recall its common preposition patterns.
Step 3: Recognise that we usually say "knowledge of English", not "knowledge in English".
Step 4: Conclude that part A is incorrect and should be corrected to "Her knowledge of English".

Verification / Alternative check:
Consider similar phrases: "His knowledge of physics is impressive", "Their knowledge of the law helps them in business." In each case, "of" is used after "knowledge". If we said "knowledge in physics" or "knowledge in the law", the phrases would sound odd or non-standard. This confirms that "in English" is wrong here and must be replaced with "of English".

Why Other Options Are Wrong:
- Part B, "gives her great advantage", is structurally acceptable in exam style, though "a great advantage" would be slightly better. The primary tested error, however, is in preposition usage in part A.

- Part C, "over me", is correctly used to show comparison ("advantage over someone").
- Part D, "No Error", cannot be chosen because we have identified a specific preposition mistake in part A.

Common Pitfalls:
Many learners translate directly from their mother tongue and use wrong prepositions with abstract nouns like "knowledge", "experience", or "research". To avoid this, pay attention to fixed patterns such as "knowledge of", "experience in", and "research on". Reading good English material and noting such combinations can greatly improve your accuracy in preposition usage.

Final Answer:
The error is in part A; the correct phrase should be "Her knowledge of English".