Question $30(1$ point$)$

$10.$ Much of the mass of the Milky Way Galaxy appears to be in the form of "dark matter" of unknown composition. At present, dark matter can be detected only because:

A$)$ it blocks out the light from distant stars in the plane of the Galaxy.

B$)$ it emits synchrotron radiation at radio wavelengths.

C$)$ its gravitational pull affects orbital motions in the Galaxy.

D$)$ it bends light from distant quasars.