Under What Circumstances Would a Molecular Geneticist Need to Use

Under what circumstances would a molecular geneticist need to use a bacterial artificial chromosome (BAC) ?

A) when cloning small, prokaryotic genomes
B) when cloning small, eukaryotic genomes
C) when cloning large, eukaryotic genomes
D) when the DNA inserts to be used for cloning are very small
E) when sequencing small proteins