The average weight of $4$ students in Class $A$ is $37$ kilograms. The average weight of $11$ students in Class $B$ is $41$ kilograms. The total weight of $5$ students in Class $C$ is $161$ kilograms. What is the average weight of the students in the $3$ classes? 
选项为:A:$36$ kilograms  B:$38$ kilograms  C:$40$ kilograms  D:$43$ kilograms  请回答其中一个选项.