Answer:
B. The distance between the slits and the screen is halved.
C. The slit width is doubled.
D. A green, rather than red, light source is used.
E. The experiment is conducted in a water-filled tank.
Explanation:
As we know that the position of first minimum is given as

so we have

so width of minimum is given as

now if we need to decrease the angular position of minimum
1). so we can decrease the distance of screen from the slit
2). we can decrease the wavelength
3). We can increase the width of the slit
So correct answer will be
B. The distance between the slits and the screen is halved.
C. The slit width is doubled.
D. A green, rather than red, light source is used.
E. The experiment is conducted in a water-filled tank.