Which of the following angles are in standard position? Select the correct option.

• A. An angle with its vertex not at the origin
• B. An angle with its vertex at the origin and its initial side along the negative $x$-axis
• C. An angle with its vertex at the origin and its initial side along the positive $y$-axis
• D. An angle with its vertex at the origin and its initial side along the positive $x$-axis

Answer: (D)

Verified step by step guidance

1. Recall the definition of an angle in standard position: it must have its vertex at the origin of the coordinate plane, and its initial side must lie along the positive x-axis.
2. Examine each option to check if the vertex is at the origin. If the vertex is not at the origin, the angle cannot be in standard position.
3. Check the position of the initial side for each angle whose vertex is at the origin. The initial side must be on the positive x-axis for the angle to be in standard position.
4. Identify that an angle with its vertex at the origin and its initial side along the negative x-axis or positive y-axis does not meet the criteria for standard position.
5. Conclude that only the angle with its vertex at the origin and its initial side along the positive x-axis is in standard position.