What is the first 24 bits in a MAC address called?

A.
NIC

B.
BIA

C.
oui

D.
vai

Explanation:
This question is to examine the MAC address structure.
The MAC address is expressed as a 48-bit hexadecimal number. The first 24-bit number is to identify the vendor/manufacturer, also called OUI. The latter 24-bit is assigned by the vendor.