Light from sun falling on a convex lens will converge at a point called A centre of curvature
B focus C radius curvature D optical centre

B

Explanation:

Light from the Sun falling on convex lens will converge at a point called a principal focus

the answer is definitely c.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).