a. It occurs when all the reflected rays from a given smooth surface are parallel for parallel incident rays.
b. This occurs from smooth surfaces like a mirror, silver spoon, etc.
c. The image is formed and seen.
a. It occurs when for a given set of incident parallel rays, the reflected rays do not remain parallel to each other.
b. This occurs from rough surfaces like wood, table, door, book, etc.
c. It helps to see objects. No images.