.Out of the following, the best way to do the experiment on finding the focal length of a concave mirror
by obtaining the image of a distant object, is to
a) hold the mirror in hand and keep the screen in a stand kept behind the mirror.
b) hold the mirror in a stand and hold the screen in hand, with the screen in front of the mirror.
c) keep both the mirror and the screen in suitable stands with the screen put in front of the mirror.
d) keep both the mirror and the screen in suitable stands with the screen put behind the mirror.