Select the correct option using $T$ (True) or $F$ (False) for the following statements:
$(1)$ $A$ mineral cannot be an ore.
$(2)$ An ore cannot be a mineral.
$(3)$ All minerals are ores.
$(4)$ All ores are minerals.

"Metals are usually not found as nitrates in their ores."
Out of the following two $(a)$ and $(b)$ reasons,which is/are true for the above observation?
$(a)$ Metal nitrates are highly unstable.
$(b)$ Metal nitrates are highly soluble in water.

Assertion : Iron is found in free state in nature.
Reason : Iron is a highly reactive element.

Main constituent of ore cassiterite is

The three most abundant elements in the Earth's crust are:

Among the following ores: Bauxite,Siderite,Cuprite,Calamine,Haematite,Kaolinite,Malachite,Magnetite,Sphalerite,Limonite,Cryolite,the number of principal ores of iron is $......$