Correct Answer - Option 3 : Both i and ii
Frog is an indentation or depression on the top face of a brick made with the object of forming a key for the mortars. This reduces the weight of the brick also.
It is kept on the top face while constructing a wall so that mortar is filled properly in it.
Size of frog = 100mm × 40mm × 10mm
Depth of frog = 10mm to 20mm
Purpose of frog:
It will provide a key for holding mortar in brick masonry
It can is used for branding purpose