Vacuum pump oil is one of the regular ....intenance liems that you will be prompted to change after approximately each __ of vacuum use. a. 30 minutes b. 60 minutes c. 8 hours d. 10 hours

## Step 1<br />The problem is asking for the approximate time after which vacuum pump oil needs to be changed. The options provided are 30 minutes, 60 minutes, 8 hours, and 10 hours.<br />## Step 2<br />The correct answer is 8 hours. This is because vacuum pump oil typically needs to be changed after approximately 8 hours of vacuum use. This is a standard maintenance guideline to ensure the optimal performance and longevity of the vacuum pump.