**A) 3**

B) 5

C) 2

D) 4

12 men took to 6 hours to complete the work.

It means there is 12 x 6= 72 units of work

Now 12men done work for one hour. So 12 x 1 =12 units of work completed.

Remaining work = 72-12= 60 units

Now the no of men=12+8= 20

So 60 units of work have to complete by 20 men

Therefore 60/20= **3 hours**