Here are the answers to the questions based on standard woodworking safety and practices:
Question 26: The minimum length of stock to run through a surfacer is C. 12 inches.
Question 27: Never change the adjustment of the B. back or outfeed table on the jointer.
Question 28: Be sure at least C. 1/2 inch/inches of the bit shank of the router is in the chuck of a router.
Question 29: When is horseplay (mischievous acts) allowed in the wood shop? A. Never
Question 30: When using a jointer, never cut deeper than B. 1/8 inch/inches. The jointer is usually set at a 1/16".
Make sure to follow proper safety guidelines and practices in woodworking!