The correct answer is (a) Any police officer.
Section 160 of the Code of Criminal Procedure 1973 states that “Any police officer, not below the rank of sub-inspector, may, in any case or class of cases, by order in writing, require the attendance before him of any person acquainted with the facts and circumstances of such case, and may examine him on oath.”
This means that any police officer, not below the rank of sub-inspector, can summon a person as a witness in any case or class of cases. The police officer does not need to be the one investigating the case.
The other options are incorrect because they are not mentioned in Section 160 of the Code of Criminal Procedure 1973.