Question

in which case do you insert a keyframe?
a when the object needs to be altered in any way
b when the object needs to stay on the stage but not change
c when the object needs to be removed from the stage
d when the object needs to become a symbol

Explanation:

A keyframe is used to mark a point in an animation where an object's properties change. When an object needs to be altered (like changing its position, size, color, etc.), a keyframe is inserted to define that specific state. Option B (object stays and doesn't change) would use a regular frame. Option C (removal) might use a blank keyframe but the core concept of change - related keyframing aligns with alteration. Option D (becoming a symbol) is about object conversion, not animation state definition.

Answer:

A. When the object needs to be altered in any way