[单选题]
The efficiency of a Carnot engine is 35.0%. What is the t9w fg o+5+rezoemperature uu 0v4c(o +nopof the cold reservoir if the temperature ofu 0u+4(o pvcon the hot reservoir is $500 ^{\circ}K$?
A. $175 \; K$
B. $325 \; K$
C. $269 \; K$
D. $231 \; K$
