Identify the error: "Some international students (i) use cassette recorders (ii) to make tapes of their classes (iii) so that they can replay the lectures (iv) again."

Choose the incorrect part:
Cans of paint must be shaking to mix the pigments with the medium in which in which they are suspended.

identify the incorrect one from the underlined sections A ray of light passing through the center of a thin lens keep its original direction.

Although both $\frac{of ~them}{\left(A\right)}$ $\frac{are\ trying}{\left(B\right)}$ $\frac{to\ get}{\left(C\right)}$ the scholarship she has the $\frac{highest}{\left(D\right)}$ grades

identify the incorrect one from the underlined sections ,Weather is the transitory expression of climate that can change great from day to day or season to season.