Which one of the following is an ore of silver?

Match the following ores with their compositions:

$A$. Calamine	$i$. $CuFeS_2$
$B$. Chalcopyrite	$ii$. $ZnCO_3$
$C$. Bauxite	$iii$. $Fe_2O_3$
$D$. Haematite	$iv$. $Al_2O_3 \cdot 2H_2O$

Match List-$I$ and List-$II$.

List-$I$ (Metal)	List-$II$ (Ores)
$a$. Aluminium	$i$. Siderite
$b$. Copper	$ii$. Calamine
$c$. Iron	$iii$. Kaolinite
$d$. Zinc	$iv$. Malachite

Choose the correct answer from the options given below:

Which of the following metals is sometimes found native in nature?

"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.

Which of the following metals is found in the native state?