[单选题]
The graph shows how the temperature of a solid *b;s h-jbpwbj-jk*:: jm hwa7wakvv o/ gb+)gn*x block varies with time. The solig +g*/)o bvknvd wax has a specific heat capacity of $2\,kJ\,kg^{−1}K^{−1}$ and it absorbs heat at a rate of 20W.
What is the specific latent heat of fusion of wax?
A. 50$J\,g^{-1}$
B. 100$J\,g^{-1}$
C. 200$J\,g^{-1}$
D. 400$J\,g^{-1}$