There are four books A, B, C and D. The requirement is that books A and B should not occupy adjacent positions among the arrangement. Treat books A and B as a single unit, then there are 3 units: AB, C, and D. These 3 units can be arranged in 3-factorial (3!) ways i.e. 6 ways. Inside the AB unit, A and B can swap their positions. So, there are 2 ways to arrange inside the AB unit. Multiply these two amounts together to get the total arrangement i.e. 6*2 = 12 ways. Hence, option 2 is correct.

Option 1 (9 ways) and option 3 (14 ways) do not figure into any of the calculations using the constraints given in the question, therefore they are incorrect.

Option 4 (18 ways) would have been correct if there was no restriction on the placement of the books A and B i.e. they can occupy continuous positions, which would have given us 4-factorial (4!) ways or 24 ways.

So, the correct answer should be option 2 (12 ways).

Alert - correct answer should be 2 (12 ways).