Question

The field of view is maximum for

Answer 1

the field view is maximum for convex mirror.  The images are diminished and so a large amount of the world is shown inside the convex mirror.  That is why it is used as a rear view mirror.

Plane mirror shows objects with same sizes of images.
In concave mirror objects at some distances are magnified, at some distances are diminished.  The virtual images in concave mirror are very enlarged. So we see very small amount of world in it.