According to the passage_________.

A Professional instruction had started before the non-profit National Association of Underwater Instructors was formed.

B Professional instruction started in 1959 when the non-profit National Association of Underwater Instructors was formed.

C Professional instruction started after the non-profit National Association of Underwater Instructors had been formed.

D Professional instruction and the non-profit National Association of Underwater Instructors were formed at the same time.