What is used to shorten wigs from the front to the nape?

The correct choice is a wig block. A wig block is a sturdy, often head-shaped structure that provides a solid surface for styling and cutting wigs. When shortening wigs from the front to the nape, it's essential to use a wig block because it allows for precise cutting while maintaining the right shape and structure of the wig. This tool helps ensure that the cut is even and that the wig maintains its desired appearance, especially when adjusting the length to create a more natural look.

In contrast, the other options serve different purposes. A wig cap is used to secure the wig onto the wearer's head and does not assist in cutting or styling. A styling comb is useful for combing and untangling hair but does not provide the stability needed for cutting. Cutting shears are essential for actual cutting but are most effective when used in conjunction with a wig block to ensure accuracy.