Which technique has NOT provided a means by which astronomers can infer the presence of dark matter in the universe?

Question

Quizplus · Accepted Answer

Measurement of the orbital speeds of stars near possible supermassive black holes at the centers of galaxies has not provided a means by which astronomers can infer the presence of dark matter in the universe. However, the other three techniques (measurement of the orbital speeds of stars in the outer regions of galaxies, observation of the bending of light from remote galaxies as it passes through intervening clusters of galaxies, and measurement of the line-of-sight speeds of individual galaxies in clusters of galaxies) have all been used to infer the presence of dark matter.

Which Technique Has NOT Provided a Means by Which Astronomers