[单选题]
A 200-L electric water heateas8)box2 2vfq 3rzha ;r uses 2 kW. Assuming no heat ec ,ohg,b7a-mloss, how long would it take o7magcbe ,h-,to heat water in this tank from $23 \; ^{\circ}C$ to $75 \; ^{\circ}C$?
A. $5 \; hours$
B. $6 \; hours$
C. $7 \; hours$
D. $8 \; hours$
