Jack Runs a Gallery That Specializes in Neon Art with Emphasis

Jack runs a gallery that specializes in neon art with emphasis on vacation icons like flamingos,dolphins and palm trees.Since demand was high,and supplies were low,he decided to buy an old warehouse and hire craftspeople to work there to produce the art.He would provide them with all of the supplies they needed,and he would be their only customer.Jack engaged in:

A) horizontal integration
B) market expansion
C) co-operative buying
D) market penetration
E) vertical integration