Answer :
Final answer:
An inside micrometer is the best tool for measuring the width of a milled slot, hole diameter, or counter-bore depth with precision and accuracy.
Explanation:
The width of a milled slot, hole diameter, or counter-bore depth can best be measured with a c) Inside micrometer. An inside micrometer is specifically designed to measure the inside dimensions of a slot or hole, giving precise and accurate measurements critical in engineering and machining tasks. Dial calipers, while versatile, may not provide the same level of accuracy for internal dimensions as an inside micrometer would. Similarly, outside micrometers and dial test indicators are more suited for measuring external dimensions and surface variations respectively.
