Step 1: Rule under Indian Evidence Act.
Confession to a police officer is generally not admissible (Section 25). However, Section 27 provides that if information leads to discovery of a fact, that part of confession is admissible.
Step 2: Magistrate confession.
A confession made to a magistrate is admissible if made voluntarily (Section 164 CrPC).
Step 3: Correct interpretation.
Thus, the admissible portion is the discovery made based on information from confession.
Step 4: Conclusion.
Hence, the correct answer is (C).