उत्तर : 3. "ऊपरी तथा निचला भू-पटल तथा आवरण का ठोस ऊपरी भाग"
व्याख्या :

The Earth's lithosphere consists of the crust and the uppermost solid mantle, which form the Earth's hard and rigid outer layer. It extends to a depth of about 100 km. The crust, as postulated by the plate tectonic theory, consists of many plates and solid blocks.