[单选题]
At what temperature is the average khw .mz.ui 7e0yuz6x ;zinetic energy of) rwulahy /alt903 vjjo18 :ls an atom in helium gas equal tyaj/vl91srua )ht0ol8l :3w j o $6.21 \times 10^{-21} \; J$?
A. $200 \; K$
B. $250 \; K$
C. $300 \; K$
D. $350 \; K$
