Depending on the radiating properties, a body will be black when_________________?

A. p = 0, x = 0 and a = 1
B. p= l,T = 0anda = 0
C. p = 0, x = 1 and a = 0
D. x = 0, a + p = 0
E. a = 0,x + p= 1.
where a = absorptivity, p == reflectivity, X = transmissivity