Match the method of concentration of the ore in column I with the
ore in column II and select the correct altemate.
`{:(,"Column "I,,"Column "II,),((a),"Leaching.",,(p)" Copper pyrite",),((b),"Calcination.",,(q)" Siderite.",),((c),"Froth floatation",,(r)" Bauxite.",),((d),"Magnetic separation.",,(s)" Chromite.",):}`

Options

A. `{:(,"(a)","(b)","(c)","(d)"),(,s,q,p,r):}`
B. `{:(,"(a)","(b)","(c)","(d)"),(,r,q,p,s):}`
C. `{:(,"(a)","(b)","(c)","(d)"),(,p,q,r,s):}`
D. `{:(,"(a)","(b)","(c)","(d)"),(,q,r,p,s):}`

Explanation

To solve the question of matching the methods of concentration of ores with the respective ores, we will analyze each method and identify the correct ore associated with it.

### Step-by-Step Solution:

1. **Leaching (a)**:
- Leaching is a process where soluble materials are separated from insoluble materials. It is commonly used for ores like bauxite, which is an ore of aluminum.
- In the leaching process, bauxite is treated with concentrated sodium hydroxide (NaOH) to form sodium aluminate, while impurities are filtered out.
- **Match**: Leaching → Bauxite (r)

2. **Calcination (b)**:
- Calcination involves heating carbonate ores in the absence of air to convert them into oxides. This process is typically used for ores like siderite (FeCO3).
- When siderite is calcined, it decomposes to form iron oxide (FeO) and carbon dioxide (CO2).
- **Match**: Calcination → Siderite (q)

3. **Froth Flotation (c)**:
- The froth flotation method is used primarily for the concentration of low-grade sulfide ores. It is effective for ores such as copper pyrite (CuFeS2) and galena (PbS).
- In this process, the ore particles are separated based on their different degrees of wettability with water and frothing agents like pine oil.
- **Match**: Froth Flotation → Copper Pyrite (p)

4. **Magnetic Separation (d)**:
- Magnetic separation is used for ores that possess magnetic properties. Chromite (FeO·Cr2O3) is one such ore that can be separated from non-magnetic impurities using this method.
- The magnetic properties of chromite allow it to be effectively separated from siliceous impurities.
- **Match**: Magnetic Separation → Chromite (s)

### Final Matches:
- (a) Leaching → (r) Bauxite
- (b) Calcination → (q) Siderite
- (c) Froth Flotation → (p) Copper Pyrite
- (d) Magnetic Separation → (s) Chromite

### Summary of Matches:
- A → r
- B → q
- C → p
- D → s