Siderite is an ore of 

Siderite $\left({\mathrm{FeCO}}_3\right)$  is an ore of iron. 

Siderite is a naturally occurring mineral and an important ore of iron (Fe). Its chemical formula is FeCO₃, which indicates that it is composed of iron (Fe) and carbonate ions (CO₃). This makes it a valuable source of iron in metallurgical processes. Below is a detailed explanation:

Why is Siderite an Ore of Iron?

• Siderite contains a significant amount of iron, making it a viable mineral for extracting the metal.
• During processing, siderite undergoes thermal decomposition to release carbon dioxide (CO₂), leaving behind iron oxides, which are further refined to extract pure iron.

Incorrect Options Explained

1. Cu (Copper): Siderite does not contain copper. Copper ores typically include chalcopyrite and malachite.
2. Al (Aluminum): Bauxite is the primary ore of aluminum, not siderite.
3. Ag (Silver): Silver is extracted from ores like argentite, not siderite.

Applications of Iron Extracted from Siderite

• Iron obtained from siderite is used in the production of steel and other alloys.
• It is also essential for manufacturing machinery, tools, and construction materials.

In conclusion, the correct answer is d) Fe, as siderite is a key ore of iron, widely used in industrial and metallurgical processes.