diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst
index 12aa0f2..cee79d9 100644
--- a/Doc/using/cmdline.rst
+++ b/Doc/using/cmdline.rst
@@ -441,10 +441,10 @@
 
 
 Debug-mode variables
---------------------
+~~~~~~~~~~~~~~~~~~~~
 
 Setting these variables only has an effect in a debug build of Python, that is,
-if Python was configured with the :opt:`--with-pydebug` build option.
+if Python was configured with the :option:`--with-pydebug` build option.
 
 .. envvar:: PYTHONTHREADDEBUG