Convex.
Concave curved inward (like how a cave foes in) and convex curves outward. Reflected and refracted do not apply to a lens.
Answer:
The distance is 
Explanation:
From the question we are told that
The wavelength of the light is 
The distance between the slit is 
The between the first and second dark fringes is 
Generally fringe width is mathematically represented as

Where D is the distance of the slit to the screen
Hence

substituting values


Answer:
I'm pretty sure the answer is runoff
A would be the correct answer. Its the only one to make sense since you are trying to solve the conflict!