Answer: The correct answer would be test tube clamps.
Step-by-step explanation:
Test tube clamp or holder is laboratory instrument used to hold a test tube in place particularly if it is hot or it is dangerous to touch it with bare hands.
For example, when a test tube is being heated it should be hold with the help of test tube clamps or when it needs to be transferred to the beaker of hot water.
An image of a test tube holder or clamp is pasted below for reference.