Match the following:
Work material
P. Aluminum
Q. Die steel
R. Copper wire
S. Titanium sheet
Type of joining
1. Submerged Arc Welding
2. Soldering
3. Thermit Welding
4. Atomic Hydrogen Welding
5. Gas Tungsten Arc welding
6. Later Beam Welding
a) P-2, Q-5, R-1, S-3 b) P-6, Q-3, R-4, S-4
c) P-4, Q-1, R-6, S-2 d) P-5, Q-4, R-2, S-6