The Current Temperature of the Cosmic Background Radiation of 2 $\mu$

Multiple Choice

The current temperature of the cosmic background radiation of 2.73 K means that the peak of its spectrum occurs at a wavelength of

A) 1 $\mu$ m.
B) 10 $\mu$ m.
C) 100 $\mu$ m.
D) 1,000 $\mu$ m.