$\begin{array}{1 1} (a)\; \text{Light speed up when it goes from a medium of higher refractive index to lower refractive index} \\ (b)\; \text{A virtual and erect image is always formed by a concave lens} \\ (c)\; \text{Lateral displacement will decrease with the decrease in thickness of the glass slab} \\ (d)\; \text{If the image formed is of the same size as that of the object, then its position should be 2F} \end{array}$
