A student obtained a sharp image of a candle flame placed at the distant end of the laboratory table on a screen using a concave mirror to determine the focal lengh. The teacher suggested him to focus a distant builiding, about 1km away form the laboratory, for getting more correct value of the focal length. in order to focus the distant building on the same screen, the student should slightly move the

Options

A. mirror away from the screen
B. screen away from the mirror
C. screen towards the miror
D. screen towards the building