The incorrect match pair is option (i). According to the context, Question 10 asks 'Why the replication of single copy plasmid called stringent replication?' This clearly indicates that stringent replication is associated with single copy plasmids, not multicopy plasmids. Multicopy plasmids have relaxed replication (multiple copies per cell). The other pairs are correctly matched: Col plasmid produces colicins that can kill bacteria, pBR322 is indeed a plasmid vector, and a prophage is correctly defined as a phage genome inserted into a host genome.