-(c) If the next sequence of characters is 'defer_FOO' followed by a comma,
-the defer behaviour is set to FOO. The possible behaviours are: 'strict', where
-any defer causes the whole lookup to defer; 'lax', where a defer causes the
-whole lookup to defer only if none of the DNS queries succeeds; and 'never',
-where all defers are as if the lookup failed. The default is 'lax'.
-
-(d) Another optional comma-sep field: 'dnssec_FOO', with 'strict', 'lax'
-and 'never' (default); can appear before or after (c). The meanings are
+(c) Options, all comma-terminated, in any order. Any unrecognised option
+terminates option processing. Recognised options are:
+
+- 'defer_FOO': set the defer behaviour to FOO. The possible behaviours are:
+'strict', where any defer causes the whole lookup to defer; 'lax', where a defer
+causes the whole lookup to defer only if none of the DNS queries succeeds; and
+'never', where all defers are as if the lookup failed. The default is 'lax'.
+
+- 'dnssec_FOO', with 'strict', 'lax' and 'never' (default). The meanings are