月亮岛西站
观沙岭站
Please solve the multiple choice problem and put your answer (one of ABCD) in one "\boxed{}". According to the subway map, how many intermediate stops are there between 月亮岛西站 and 观沙岭站 (except for this two stops)? 
A) 21 
B) 16 
C) 4 
D) 22 
