Which one of the following properties makes plasmids suitable vectors for gene cloning?

Question

$\begin{array}{1 1} (a)\;\text{ Plasmids are small, circular DNA molecules that can integrate with host chromosomal DNA} \\ (b)\;\text{ Plasmids are circular DNA molecules with their own replication of origin site } \\ (c)\; \text{ Plasmids can shuttle between prokaryotes and eukaryotes} \\ (d)\; \text{ Plasmids often carry antibiotic resistance gene} \end{array}$