Right answer is (b) 2
The explanation is: Generally drawing board has dimensions of 1000 x 1500, 700 x 1000, 500 x 700, 350 mm x 500 mm, and made of well-seasoned soft wood, so there would be no bending while life increases. And also if a size of drawing board increases widely then the board will be fabricated with another 1 or 2 battens.