This problem requires matching metallurgical conversion processes from Column I with the corresponding type of reaction(s) from Column II. Let's analyze each conversion step-by-step.

Definitions of the processes in Column II:

• (P) Roasting: Heating an ore, usually a sulfide ore, in a regular supply of air at a temperature below its melting point. This process is typically used to convert sulfide ores into their corresponding oxides.
• (Q) Calcination: Heating an ore strongly in a limited supply or absence of air. This process is used for carbonate or hydrated oxide ores to remove volatile impurities like CO₂ or H₂O.
• (R) Carbon reduction: A process where a metal oxide is reduced to the metal by heating it with carbon (usually in the form of coke). It is used for moderately reactive metals.
• (S) Self-reduction (or Auto-reduction): A process used for the extraction of less electropositive metals like Cu, Pb, and Hg. In this method, the sulfide ore is partially roasted to form an oxide, which then reacts with the remaining sulfide ore to yield the metal.

Analysis of Conversions in Column I:

1. (A) PbS → PbO

• This conversion involves heating lead(II) sulfide (galena ore) in the presence of air to form lead(II) oxide.
• The chemical reaction is: $2PbS + 3O_2 \xrightarrow{\Delta} 2PbO + 2SO_2$
• Heating a sulfide ore in the presence of air is the definition of roasting.
• Therefore, (A) matches with (P).

2. (B) CaCO₃ → CaO

• This conversion shows the thermal decomposition of calcium carbonate (limestone) into calcium oxide (quicklime) and carbon dioxide.
• The reaction is: $CaCO_3(s) \xrightarrow{\Delta} CaO(s) + CO_2(g)$
• This process involves heating a carbonate ore in the absence of air to drive off CO₂. This is the definition of calcination.
• Therefore, (B) matches with (Q).

3. (C) ZnS → Zn

• The extraction of zinc from zinc sulfide (zinc blende) involves two main steps:
  • Step 1: The ZnS ore is first converted to zinc oxide (ZnO) by heating it in excess air. This is roasting (P). $2ZnS + 3O_2 \xrightarrow{\Delta} 2ZnO + 2SO_2$
  • Step 2: The resulting zinc oxide is then reduced to zinc metal using carbon (coke) as a reducing agent at high temperatures. This is carbon reduction (R). $ZnO + C \xrightarrow{\Delta} Zn + CO$
• Thus, the overall conversion from ZnS to Zn involves both roasting (P) and carbon reduction (R).
• Therefore, (C) matches with (P) and (R).

4. (D) Cu₂S → Cu

• The extraction of copper from copper(I) sulfide (chalcocite) is a key part of copper metallurgy and involves self-reduction.
  • Step 1: The Cu₂S ore is partially heated in a controlled supply of air to form some copper(I) oxide. This step is a form of roasting (P). $2Cu_2S + 3O_2 \xrightarrow{\Delta} 2Cu_2O + 2SO_2$
  • Step 2: The supply of air is then cut off, and the temperature is raised. The copper(I) oxide formed reacts with the remaining copper(I) sulfide to produce molten copper. This is self-reduction (S), as the sulfide ore itself acts as the reducing agent. $Cu_2S + 2Cu_2O \xrightarrow{\Delta} 6Cu + SO_2$
• Therefore, the overall conversion from Cu₂S to Cu involves both roasting (P) and self-reduction (S).
• Therefore, (D) matches with (P) and (S).

Final Matching:

• (A) → (P)
• (B) → (Q)
• (C) → (P, R)
• (D) → (P, S)

Comparing this with the given options:

• A: A→(p); B→(q); C→(p); D→(s) - Incorrect, C and D are incomplete.
• B: A→(q); B→(p); C→(r); D→(p, s) - Incorrect, A, B are wrong, and C is incomplete.
• C: A→(p); B→(q); C→(p, r); D→(p, s) - Correctly matches all our findings.
• D: A→(p); B→(q, s); C→(p, r); D→(p) - Incorrect, B is wrong, and D is incomplete.

Thus, option C is the correct choice.