Which of the Following Statements with Regard to Portland Cement are Correct?
1. Sillica imparts strength to cement.
2. Alumina makes the cement quick setting.
3. Excess of lime increases the strength of cement
4. Calcium sulphate decreases the initial setting time of cement.
Select the correct answer using the code given below
(a) 2 and 4 only (b) 1 and 3 (c) 1, 2 and 4 (d) 1 and 2 only