单项选择题
A.htpasswd-c/usr/local/nagios/etc/htpasswd.usersnagiosadmin
B.htpasswd-s/usr/local/nagios/etc/htpasswd.usersnagiosadmin
C.htpasswd-d/usr/local/nagios/etc/htpasswd.usersnagiosadmin
D.htpasswd-a/usr/local/nagios/etc/htpasswd.usersnagiosadmin