The correct answer is (a) Convex mirror.
A convex mirror is a curved mirror that bulges outward at the center. It forms a virtual image that is always upright, smaller than the object, and located behind the mirror. Convex mirrors are often used in rearview mirrors because they provide a wide field of view.
A concave mirror is a curved mirror that bulges inward at the center. It forms a real image that can be either upright or inverted, depending on the position of the object. Concave mirrors are often used in telescopes and microscopes to magnify objects.
A plane mirror is a flat mirror. It forms a virtual image that is upright, the same size as the object, and located behind the mirror. Plane mirrors are commonly used in bathrooms and bedrooms.
A spherical mirror is a mirror that has the shape of a part of a sphere. There are two types of spherical mirrors: convex mirrors and concave mirrors.