7. The distance between the slits in a double-slit experiment is increased by a factor of 4. If the distance between the fringes is small compared with the distance from the slits to the screen, the distance between adjacent fringes near the centre of the interference pattern: a. increases by a factor of 2. b increases by a factor of 4. c depends on the width of the slits. d. decreases by a factor of 2. e decreases by a factor of 4