Consider a camera lens whose focal length is $40$ mm$.$ This lens has to be at a distance of $40$ mm from the film when focused on distant mountains. To take a picture of a person who is $0\mathrm{.}8$ m in front of the lens, at what distance from the film should the lens be moved so that the image of the person is in focus on the film, and what happens to the image of the distant mountains in the background?

$42\mathrm{.}1$ mm from the film, and the background is also in focus$42\mathrm{.}1$ mm from the film, and the background is blurred$2\mathrm{.}1$ mm from the film, and the background is blurred$2\mathrm{.}1$ mm from the film, and the background is also in focus