Question

what type of rotary bits can cause a grinder to catch on rough material edges or shift around? abrasive backing kerf burr

Explanation:

Abrasive rotary bits are designed to grind or cut through materials. Their rough surface can catch on uneven edges of the material being worked on. Backing refers to the support structure for abrasive materials (not the bit itself causing catching). Kerf is the width of the cut made by a tool. Burr is a raised edge or small piece of material left on a workpiece after machining. So, abrasive bits are the ones that can cause the described issue.

Answer:

A. abrasive