For greater accuracy, some micrometers have a vernier scale making it possible to read in increments of __________.

Correct Answer: Option D — ten thousands of an inch

Standard micrometers typically read to one-thousandth of an inch. By incorporating a vernier scale on the barrel, the tool allows for an additional decimal place of precision, enabling measurements down to ten-thousandths of an inch. This level of accuracy is vital for verifying tight-tolerance clearances in precision marine machinery.