Also see definition of "Interrogation" in Word Study
Study Dictionary
Interrogation
INTERROGATION [ISBE]
INTERROGATION - in-ter-o-ga'-shun (eperotema): This word is not found at all in the King James Version, and once only in the American Standard Revised Version (1 Pet 3:21), where it replaces the word "answer" of the King James Version. This change according to Alford and Bengel is correct. "The interrogation of a good conscience" may refer to the question asked of a convert before baptism (compare Acts 8:37), or the appeal of the convert to God (compare 1 Jn 3:20-21). The opportunity to do this was given in baptism.
Also see definition of "Interrogation" in Word Study