You are looking for an executable file foo. Select the command that would search forfoo within directories set in the shell variable， PATH.（）

A. export LD_PRELOAD=/usr/local/lib
B. export LD_LIBRARY_PATH=/usr/local/lib
C. Idconfig /usr/local/lib
D. Idd/usr/local/lib

A. ：!ls-I myfile
B. ：\ls-l myfile
C. esc ：Is -I myfile
D. ：？ls-l myfile

A. kill-1 123
B. kill-9 123
C. kill-15 123
D. kill-17 123