QUESTION 60
The following SAS program is submitted:data work.passengers;
data work.passengers;
if OrigPassengers = . then
OrigPassengers=100;
TransPassengers= 100;
OrigPassengers= .;
NonPaying= 10;
TotalPassengers= OrigPassengers + TransPassengers;
run;
Which one of the following is the value of the TOTALPASSENGERS variable in the
output data set?
A. 100
B. 110
C. 200
D. . (missing numeric value)

D是答案，不是可以忽略missing value吗？为什么这里不可以忽略？真的要抓狂了

谢谢！