In the Kraft process of sulphate paper pulp manufacture, the black liquor and the white liquor storage tank is made of _______________?

In the Kraft process of sulphate paper pulp manufacture, the black liq

1.	In the Kraft process of sulphate paper pulp manufacture, the black liquor and the white liquor storage tank is made of _______________?
A.	Concrete
B.	Wood
C.	Steel
D.	Porcelain
Answer» D. Porcelain