Correct option is A
The constituents of good brick earth:
Lime:
For good brick earth, it is desirable not to have lime more than 5%. Lime prevents the shrinkage of raw bricks. Excess of Lime causes the brick to melt and therefore its shape can be lost.
Alumina:
It is the chief constituent of every kind of clay. This constituent imparts plasticity to the earth so that it can be molded.
Silica:
The presence of this constituent prevents the cracking, shrinking, and warping of raw bricks. It thus imparts a uniform shape to the bricks.
Oxide of iron:
It acts as a catalyst in the fusion of ingredients of bricks. It also imparts a red color to the bricks.
