The number of flops required for construction a MOD 12 counter is ______.

Correct option is C

The necessary condition for the number of flip-flops required is: $$n^2 \geq \text{Number of MOD}$$

We substitute values for 

$n=1,2,3,4,5$:

​$$1^2 = 1$$

$$2^2 = 4$$

$$3^2 = 9$$​​​​

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