The chromatic number of the following graph is _________ .


(A) 2
(B) 3
(C) 4
(D) 5


Answer: (B)

Explanation: Since given graph is planar graph so it can not be chromatic number greater than 4 and also it has odd lenght cycle so it can not be less than 3.

In fact, given graph has chromatic number is 3 as following below:

Option (B) is correct.

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