To answer this question, we need to understand the correct usage of negative agreement.
In English, when we want to agree with a negative statement or express a negative opinion, we typically use the word "neither" followed by an auxiliary verb or a modal verb, and then the subject.
Let's go through each option to understand why it is correct or incorrect:
Option A) "So do I" - This option is incorrect because it does not use the correct form of negative agreement. Instead, it is used to agree with a positive statement.
Option B) "Neither do I" - This option is correct because it follows the correct form of negative agreement. "Neither" is used to agree with a negative statement, and "do" is the auxiliary verb that agrees with the tense of the original statement. The subject "I" is placed after the auxiliary verb.
Option C) "Neither I did" - This option is incorrect because the word order is incorrect. In negative agreement, the subject should come after the auxiliary verb or modal verb.
Option D) "Neither did I" - This option is correct because it follows the correct form of negative agreement. "Neither" is used to agree with a negative statement, and "did" is the auxiliary verb that agrees with the tense of the original statement. The subject "I" is placed after the auxiliary verb.
The correct answer is Option D. This option is correct because it correctly uses the form of negative agreement.