A flare is dropped from an airplane flying horizontally at uniform velocity (constant speed in a straight line). Neglecting air resistance, the flare will:. A) quickly lag behind the plane B) remain vertically under the plane C) move ahead of the plane explain

Option B (remain vertically under the plane) is the correct option.

Explanation:

A flare would follow a particle trajectory with horizontal direction somewhat like airplane velocity as well as initial maximum motion as null but instead, gravity will induce acceleration. It would be lowered vertically underneath the plane before flare had already sunk to something like the surface.There is no different movement in the airplane nor even the flash. And none of them can change its horizontal level.  

Some other alternatives are given really aren't linked to the specified scenario. So choice B is the perfect solution to that.

2. they have negligible mass.