Correct Option: A

The yeast artificial chromosome (YAC) is an artificially constructed system that can undergo replication. The design of a YAC allows extremely large segments of genetic materials to be inserted. Subsequent round of replication produce many copies of the inserted sequence, is a genetic procedure known as cloning. The reason the cloning vector is called the YAC has to do with the structure of vector.YACs are shuttle vector that can be amplified in bacteria and employed for the cloning and the manipulation of large DNA inserts (up to 3mb pairs) in the yeast-Saccharomyces cerevisiae. Large DNA (>100 Kb) is ligated between two arms.