[单选题]
A monatomic gas is cooled by 50 K at constant volume when ry14h1b )4a9 bs ksvxh831 J of t 4yaygg4m- c,energy is removed fro4-ytcgy4 ,m agm it. How many moles of gas are in the sample?
A. $2.50 \; mol$
B. $1.50 \; mol$
C. $1.33 \; mol$
D. none of the above
