The Background Microwave Radiation, Discovered in 1965 by Penzias and Wilson

Multiple Choice

The background microwave radiation, discovered in 1965 by Penzias and Wilson, has its peak intensity at a wavelength of 1.06 mm. What blackbody temperature does this wavelength imply for the universe? (σ = 5.670 × 10^-8 W/m² ∙ K⁴, Wien displacement law constant is 2.90 × 10^-3 m ∙ K)

A) 2.7°C
B) -270°C
C) 0.0027 K
D) 0.00°C
E) -2.7°C