Question

select the test - tube holder.

Explanation:

A test - tube holder is a laboratory tool used to hold test - tubes, especially when they are hot (e.g., after heating). The first image shows a typical test - tube holder with a long handle and a gripping part for the test - tube. The second image appears to be a different laboratory tool (maybe a ring - shaped holder for other purposes, not specifically for test - tubes in the common sense). The third image looks like a pair of tweezers or another type of gripping tool not designed for test - tubes.

Answer:

The first image (the one with the long handle and the test - tube gripping part) is the test - tube holder.