In this English grammar error spotting question, one part of the sentence may be incorrect in terms of prepositions or expressions. Identify the part that has an error, or choose the "No error" option. Sentence: The main purpose of the visit is to develop a close relationship among the two countries.

Introduction / Context:
This error spotting question tests your knowledge of correct prepositions used to describe relationships involving two entities. The sentence talks about the purpose of a visit and the relationship between two countries. Choosing the correct preposition is essential for natural and accurate English.

Given Data / Assumptions:
- Full sentence: The main purpose of the visit is to develop a close relationship among the two countries.
- Part A: The main purpose of the visit
- Part B: is to develop a close relationship
- Part C: among the two countries
- Part D: No error

Concept / Approach:
In English, we use "between" when referring to a relationship involving two people, countries, or things. We use "among" when referring to relationships involving more than two. Since the sentence clearly mentions "the two countries", the correct preposition should be "between", not "among". Therefore, the error lies in part C of the sentence.

Step-by-Step Solution:
Step 1: Identify the subject of the preposition in part C: "the two countries". Step 2: Recall the rule that "between" is used for two things, while "among" is for more than two. Step 3: Recognise that "among the two countries" violates this rule. Step 4: Mentally correct the phrase to "between the two countries". Step 5: Since this error is isolated in part C, choose C as the answer.

Verification / Alternative check:
Consider similar sentences: "The agreement between the two companies" or "Friendship between the two neighbours". You would not usually say "among the two companies". Grammar references confirm that when exactly two parties are mentioned, "between" is preferred. This verifies that the word in part C should be "between", not "among".

Why Other Options Are Wrong:
Part A correctly introduces the subject and purpose of the visit. Part B uses a correct infinitive phrase "to develop a close relationship". Part D, "No error", cannot be correct because we have clearly identified a preposition error in part C. Option E, saying there is no error in any part, is also ruled out for the same reason.

Common Pitfalls:
Students sometimes overuse "among" because they have heard it in the phrase "among the people" or "among the nations" without noticing the number involved. A helpful memory trick is to think "between two, among many". Keeping this simple rule in mind will help you answer many similar questions quickly and accurately.

Final Answer:
The error is in part C, because the phrase should be "between the two countries", not "among the two countries".