[单选题]
A thin metal plate of mass m is held at an absolute ta9wry-s/iaw s( *ic1w emperature cc 7n6dhl-a*qo(o+rsq)c2imon; 4 h zT, in an enclosure 4o +a 6dqnomioc7*; zq2nhcr-sc )lh(of temperature $T_s$
A. $\frac{σAT^4Δt}{m(Δt}$
B. $\frac{σA(T^4-T_s^4)Δt}{m(Δt}$
C. $\frac{2σAT^4Δt}{m(Δt}$
D. $\frac{2σA(T^4-T_s^4)Δt}{m(Δt}$