The question said we should determine from the option which amongst it represent the length of the line segment drawn.
One the we must first point out is that when writing the length of asny segment, just write the start point and end of the segment.
From the options given, we will determine the following:
In option (A) B is not equal = 6
In option (C) is the name of the segment
In option (D) A is a point can not = 6
The answer is option B, which is AB = 6.
