Which code snippet contains the correct query?

The following excerpt is from a Perl script that reads from an LDAP database and writes an LDIF file:
Which code snippet contains the correct query?

A.
$mesg = $ldap->search(
base => ‘o=inc’,
);

B.
$mesg = $ldap->search(
base => ‘cn=incadmin,o=inc’,
scope => ‘one’,
filter => ‘(objectclass=*) ‘
);

C.
$mesg = $ldap->search(
base => ‘o=inc’,
scope => ‘sub’,
filter => ‘(objectclass=*)’
);

D.
$mesg = $ldap->search(
base => ‘o=inc’,
recursive => ‘yes’,
filter => ‘(*) ‘
);