Which tool would you use to add keyframes in Premiere Pro?

The Pen tool is the correct choice for adding keyframes in Premiere Pro because it allows you to create and manipulate keyframe animations directly on the timeline for effects and properties. By using the Pen tool, users can place keyframes at specific points in time, enabling a more precise and intuitive approach to animation within clips. This tool is especially useful for adjusting motion paths, opacity, and audio levels, giving users granular control over how these parameters change over time.

In contrast, the other tools serve different purposes that do not relate directly to adding keyframes. The Cut tool and Razor tool are primarily used for splitting clips in the timeline, creating cuts, and dividing footage into separate sections, while the Selection tool allows you to select, move, and resize clips but does not specifically facilitate the addition of keyframes.