Answer:
A. decrease the slit separation
Explanation:
Double slit experiment was done to study the phenomenon of interference of light. It gives a definitive proof of wave nature of light.
In the double slit experiment
the distance between the fringes in the interference pattern is given by
[tex]\Delta y = \frac{\lambda D}{d}[/tex]
D= distance between the slit and the screen
d= distance between the slits
λ= wavelength
therefore, and increase in Δy may decrease d that is
:A. decrease the slit separation