Where should an object be placed in front of a concave mirror so that the size of its image is equal to the size of the object, given that rays from the sun converge at a point 15 cm in front of the mirror?

a) 30 cm in front of the mirror
b) 15 cm in front of the mirror
c) 45 cm in front of the mirror
d) It is not possible with a concave mirror.