251. In a colar beam roof_______________?

A. there is no horizontal tie beam
B. there is a horizontal tie at the feet of rafters only
C. there is a horizontal tie at almost the middle of rafters only
D. there are two horizontal ties, one at the feet and other at the middle of the rafters
✅ The correct answer is option C.

256. Advantage of a clamp compared to a kiln for burning bricks is that_______________?

A. it takes less time for burning
B. it gives more output of first class bricks
C. it has less initial cost
D. it is suitable when bricks are required in large numbers
✅ The correct answer is option C.