Topic : some important compounds of transition elements

Correct formula of calamine is

Which among the following is an oxide ore of metal?

An ore of zinc among the following is

Consider the following reaction,

MnO₂ --(Fused with KOH, oxidized with air)--> A --(Electrolytic oxidation in alkaline solution)--> B

The colour of B is

Siderite, a mineral of iron is chemically