Step 1: Analyze the question.
The question asks to compare the two quantities, where \( x \) is a line segment from the center of the circle to a point inside the circle. It is compared with 5.
Step 2: Understanding the circle.
In the given circle, the two line segments shown are from the center to a point inside the circle, meaning they represent radii of the circle.
Step 3: Conclusion.
Since the line segment \( x \) is shorter than the radius of the circle, and the radius of the circle is represented by 3, which is less than 5, we conclude that \( x \) must be smaller than 5. Hence, the correct answer is that Quantity A is greater.
Final Answer:
\[
\boxed{\text{The correct answer is (A) Quantity A is greater.}}
\]