The MAC address for your PC NIC is: C9-3F-32-B4-DC-19. What is the address of the OUI portion of this NIC card, expressed as a binary number?

A. 11001100-00111111-00011000
B. 11000110-11000000-00011111
C. 11001110-00011111-01100000
D. 11001001-00111111-00110010
E. 11001100-01111000-00011000
F. 11111000-01100111-00011001

Answer: D

Explanation:
The first half of the address identifies the manufacturer of the card. This code, which is
assigned to each manufacturer by the IEEE, is called the organizationally unique
identifier (OUI). In this example, the OUI is C9-3F-32. If we take this number and
convert it to decimal form we have:

C9 = (12x16) + 9 = 201
3F = (3x16) + 15 = 63
32 = (3x16) + 2 = 50

So, in decimal we have 201.63.50. If we then convert this to binary, we have:
201 = 11001001
63 = 00111111
50 = 00110010

So the correct answer is D: 11001001-00111111-00110010