Step 1: Understanding the Question:
The task is to identify the part of the sentence that contains a grammatical error. This question tests subject-verb agreement.
Step 2: Key Formula or Approach:
The grammatical rule to apply here is that indefinite pronouns like "Neither", "Either", "Each", "Everyone", and "Anyone" are singular and must take a singular verb.
Step 3: Detailed Explanation:
1. Identify the subject: The subject of the sentence is "Neither of the two brothers". The core subject is "Neither", which is singular.
2. Identify the verb: The verb used is "are", which is a plural verb.
3. Check for agreement: A singular subject ("Neither") requires a singular verb. The singular form of "are" is "is".
4. Locate the error: The use of the plural verb "are" with the singular subject "Neither" is incorrect. The phrase "are ready" contains the error. It should be "is ready".
The corrected sentence would be: "Neither of the two brothers is ready to go."
Step 4: Final Answer:
The error lies in the part "are ready". Therefore, option (C) is the correct answer.