[单选题]
50 g of lead ($c = 0.11 \; kcal/kg \cdot ^{\circ}C$) at $100 \; ^{\circ}C$ is put into 75 g of water at $0 \; ^{\circ}C$. What is the final temperature of the mixture?
A. $2 \; ^{\circ}C$
B. $6.8 \; ^{\circ}C$
C. $25 \; ^{\circ}C$
D. $50 \; ^{\circ}C$
