Read each sentence to find out whether there is any grammatical error in it. The error, if any will be in one part of the sentence. The letter of that part is the answer. If there is no error, the answer is 'D'. (Ignore the errors of punctuation, if any). (solve as per the direction given)

The sentence reads: "The presumption that the average investor does not understand or take interest in the affairs of the company is not correct." Let's break it down to identify any grammatical error:

1. Option A - The presumption that the average investor does not understand:
   • This part is grammatically correct. The subject "The presumption" is followed by the noun clause "that the average investor does not understand," which is fine in terms of structure and tense.
2. Option B - or take interest in the affairs of the company:
   • This part is also correct. The conjunction "or" properly connects "understand" and "take interest" in a parallel structure, indicating two actions the average investor is presumed not to do.
3. Option C - is not correct:
   • This part is correct. The verb "is" agrees with the subject "The presumption," and the phrase "is not correct" is properly used to negate the statement made in the sentence.
4. Option D - No error:
   • There are no grammatical errors in any part of the sentence. The sentence is well-constructed and clear.
5. Final Answer:
   • The sentence is free of errors, so the correct answer is D. No error.