Question

select the volumetric flask.

Explanation:

A volumetric flask has a round - bottom and a long, narrow neck with a single calibration mark. The first image is a beaker (wide, with multiple measurement lines). The third image is a graduated cylinder (long and narrow with multiple measurement lines). The second image has a round - bottom, a long narrow neck, and a single calibration mark which are the characteristics of a volumetric flask.

Answer:

The second image (the one with a round - bottom, long narrow neck, and a single "100 mL" calibration mark) is the volumetric flask.