Final answer:
The Tapered Fissure dental bur is used for providing angles to the walls of a prepared tooth due to its design that allows for precision in creating converging walls and flat floors in cavity preparations.
Step-by-step explanation:
The type of dental bur that helps to provide angles to the walls of a prepared tooth is C) Tapered Fissure. This dental bur is designed to create converging walls and flat floors in cavity preparations. The shape allows for precise cutting and shaping of the enamel and dentin, and it is particularly useful for forming the internal walls of a cavity. Other burs like the round bur are used for decay removal and creating retention in cavity preparations, while pear burs can be used for creating rounded internal line angles. The crosscut fissure is similarly shaped to the tapered fissure but has a serrated edge, which is mainly used for cutting through metal such as crown and bridge preparations.