Second class bricks

ANS:B - produce a metallic sound when struck

A class bricks produce metallic sound.
B class bricks are over burnt.
c class bricks are under burnt. 1st- gives metallic sound.
2nd- slightly over burnt or well burnt.
3rd- underburnt.
Jahma - Dark brown colour. I think given option is correct because in first class brick give Clear metallic sound when struck with each other.B option is Correct.
First class and Second Class, both produce metallic ringing sound because of hardness property.
Second class brick is slightly over burnt.
Dark brown/bluish colour is of Jahma bricks.