55 The following SAS program is submitted:
data work.flights;
destination = 'CPH';
select(destination);
when('LHR') city = 'London';
when('CPH') city = 'Copenhagen';
otherwise;
end;
run;
Which one of the following is the value of the CITY variable?
A. London
B. Copenh
C. Copenhagen
D. ' ' (missing character value)
  答案是B

59 The following SAS program is submitted:
data work.staff;
JobCategory = 'FA';
JobLevel = '1';
JobCategory = JobCategory || JobLevel;
run;
Which one of the following is the value of the variable JOBCATEGORY in the output data set?
A. FA
B. FA1
C. FA 1
D. ' ' (missing character value)
  答案是A

请问哪位高手能帮助解释一下这两道题？非常感谢！