What causes a continental shield to form?

Athe formation of mountains and their subsequent erosion at convergent plate boundaries
Bthe subduction of oceanic lithosphere under continental lithosphere
Cthe partial melting of magma under a continent
Dthe collision between two plates of continental crust

The stable platform has developed from a series of _____.

Amountain belt erosion followed by isostatic adjustment
Bvolcanic eruptions that deposit thick layers of lava followed by periods of metamorphism
Crising and falling sea levels and their accompanying cycles o

Explanation: Continental shields are the region within the continent where there is no active tectonism or it can be considered to be a stable region. Continental shields are formed in the region where partial melting of the crust takes place and the magma rises up and gets cooled because of the low temperature and gets solidified forming crystalline rocks such as granite.

In due course of time, partial melting below the crust stops and the crystallized rocks gets metamorphosed and forms a stable craton.

Thus the correct answers are option (C) and (B).