Match the phases of steel in Group I with the crystal structures in Group II.

Group I	Group II
P. Martensite	1. bcc
Q. Cementite	2. fcc
R. Austenite	3. bct
S. Ferrite	4. Orthorhombic

A. Dislocation pile-up B. Large number of slip systems C. Low stacking faultenergy D. Dislocation climb

A. Lamellar B. Widmanstatten C. Acicular D. Nodular

A. decreases because the oxygen ions supplied by the sodium oxide break the chain structure of the silicate slag B. increases because the oxygen ion supplied by the sodium oxide further add to the oxygen network in the slag C. remains unaffected because fundamentally one can not distinguish between the oxygen ions supplied by the sodium oxide and those already present in the slag D. remains unaffected because the oxygen ions fill up the holes and vacancies present in the liquid slag

A. P-4, Q-3, R-2, S-1 B. P-1, Q-2, R-3, S-4 C. P-2, Q-4, R-1, S-3 D. P-2, Q-4, R-3, S-1