What type of Studio Spline lets you create a spline by constructing and manipulating spline poles?

The correct answer is the type of Studio Spline that allows you to create a spline by constructing and manipulating spline poles. When working with this type of spline, the construction relies on defining key points in the spline's shape known as poles. These poles serve as control points, forming the framework over which the spline is shaped. By moving and adjusting these poles, you can influence the curvature and overall design of the spline, allowing for intuitive and flexible shape creation.

In contrast, a spline defined "By Points" would focus on specific points that the spline must pass through, leading to a more constrained shape. "By Control Vertices" involves manipulating vertices that directly influence the curve but are generally more suited to a different context in spline modeling. "By Edges" refers to splines created with respect to existing edges, which is distinct from the pole-based construction method. Thus, the option that specifically involves the manipulation of spline poles to create and refine the shape of the spline is the most appropriate choice.