She did not know the answer, and ______?

A. I did not neither
B. I did neither
C. neither did I
D. neither I did

Answer and Explanation

She did not know the answer, and neither  did I

Here, NEITHER DID I is the correct answer because in such a situation
we use the following structures only
neither/nor + auxiliary/modal verb + subject

Furthermore,
We can also use the subject + auxiliary verb + not + either 

So, here according to this structure we get only two sentences which are as under

I did not either  OR neither did I