The answer to your question is answer B. Dial indicators can also make other measurements. Not just shaft eccentricity and depending on how the dial is setup you may need to read the movement that travels negative and positive and you may be asked to provide the total movement. It is possible to set up a dial indicator so you only read positive movement but it's not realistic and often difficult to always zero the dial needle to do this. I hope your instructor is not someone who has taught to always setup the dial to only read positive needle movement.

@@DrivelineMaster thank you very much, im so much brighten to this answer. Please keep safe and God bless.

I will look into it.

I found an online translator. I have no idea if it is accurate. I didn't even know I could add additional subtitle languages so thank you for asking. Please let me know if the google translation is accurate.

Please take a close look at time stamp 4:15. I note that the tip is rounded with a tiny ball bearing specifically for measurements when the dial indicator can not be perfectly perpendicular to the measured movement. This will easily be accurate to less than 0.0005" which is more than accurate enough for all automotive applications.

While it might not matter to your parameters, it is still good practice to ensure accuracy in other applications. Any competent inspector would laugh at this setup.

@@fredfowler4364 This is general practice in the automotive world and works well for this industry. The technician should always use a rounded tip and get it as straight as possible. Automotive applications typically have a tolerances of 0.001" to 0.003" so we can get by with this type of setup. If someone is in an industry where super accuracy matters then absolutely accurate measurement setup is imperative. Thanks for your input.