A line segment $RS$ symbolically written as:
A.$RS$
B.$\overleftrightarrow {RS}$
C.$\overrightarrow {RS} $
D.$\overline {RS} $

Hint: Use the basic notation for a line and also for a line segment and also the basic definitions of the line and the line segment and also differentiate both of them.

Complete step-by-step answer:
When a one point is extended upto infinity, then it is called a ray and when it is ended at a point, then the ray is called a line.
A line joining the two points $A$ and $B$ is written as $\overleftrightarrow {AB}$. A line segment is a part of the line which makes it a segment.
So, the line segment is always smaller than the line and the notation for the line segment is $\overline {CD} $, where $C$ and $D$ are the endpoints of the line segment taken from the line.
So, line segment $RS$ is symbolically written as $\overline {RS} $.
So, the correct answer is “Option D”.

Note: The main difference between the line and line segment is that line segment is a part of the line and the line segment is always smaller than the line it is being taken from.