Regarding organizational buying, the people who have the power to select or approve the supplier- especially for larger purchases- are called:

Abuyers.
Binfluencers.
Cdeciders.
Dusers.
Egatekeepers.

Verified Answer :

In general, the people who have the power to select or approve the supplier are referred to as the "buyers". Most of the time, buyers want to go with a supplier who can offer the best product at the cheapest price.