Which of the following best describes the terminal side of an angle in standard position?

• A. It is the initial side of the angle, always lying along the positive $x$-axis.
• B. It is the side of the angle that always lies along the negative $y$-axis.
• C. It is the side of the angle that rotates from the initial side to form the angle.
• D. It is the side of the angle that remains fixed on the origin.

Answer: (C)

Verified step by step guidance

1. Recall that an angle in standard position is drawn with its vertex at the origin of the coordinate plane and its initial side along the positive x-axis.
2. Understand that the initial side of the angle is fixed and does not move; it always lies along the positive x-axis.
3. The terminal side of the angle is the side that rotates from the initial side to form the angle. This side can lie anywhere depending on the measure of the angle.
4. Note that the terminal side is not fixed along any particular axis (like the negative y-axis) unless the angle specifically measures 270 degrees or an equivalent angle.
5. Therefore, the terminal side is best described as the side of the angle that rotates from the initial side to form the angle.