Sas adv 有一题目是这样的:

Given the following options statement:
Libname A 'SAS library reference';
Libname F 'SAS library reference';
options fmtsearch=( A  F.X);
What is the second location searched for formats?

A. F.X
B. A.FORMATS
C. WORK.FORMATS
D. SAS supplied formats

Answer is C.  
哪位大虾知道Work library 为什么在第2位search 呢?谢谢