[单选题]
On a cold day, a piece of metal f(w67w3hoybe ,cwvv d pg;*v,u)ton+qey,;g rm;c s/zlels much colder to the touch than a piece of wood. This is due to the difference in which one of the following physical properycl rsz/g ,m;;ty?
A. density
B. specific heat
C. latent heat
D. thermal conductivity
