Read the sentence given below to find out if it contains any error. The error, if any, will be only in one part of the sentence. If the sentence is error-free, select No Error or Option 5(E). Ignore errors of punctuation, if any.

I feel extremely embarrassed (A)/ to say this but the person with (B)/ who I fought (C)/ last night was my friend. (D)/ No error (E)