Option C: sections of plate boundaries that have not ruptured in the recent past.

CDS 2015 PYQ with Answer — Seismic gaps are

2015 · Q116

Seismic gaps are

General KnowledgeGeography

Aparts of plate boundaries in oceans where tsunamis occur frequently.
Bsections of plate boundaries that have ruptured repeatedly in the recent past.
Csections of plate boundaries that have not ruptured in the recent past.
Dplate boundaries having no volcanic activity.

Explanation

Seismic gaps are sections of plate boundaries (faults) that have not ruptured in the recent past and are therefore regarded as likely sites of future earthquakes. The answer is C.