Olivine is the good source of

Olivine is a silicate mineral that is rich in magnesium and iron and is commonly found in igneous rocks.

Its chemical composition mainly contains magnesium silicate minerals, making it an important natural source of magnesium in soils and rocks.

When olivine weathers, it releases magnesium (Mg) into the soil, which is an essential nutrient required for plant growth and chlorophyll formation.

Although olivine may contain small amounts of other elements, it is primarily recognized as a good source of magnesium rather than boron, calcium, or molybdenum.

Therefore, Option B: Mg is the correct answer.