Fix plural.
diff --git a/Misc/Porting b/Misc/Porting
index ec9cf1f..51f73e6 100644
--- a/Misc/Porting
+++ b/Misc/Porting
@@ -31,7 +31,7 @@
 it out of the config.c file.
 
 Bang on it until you get a >>> prompt.  (You may have to disable the
-importing of "site.py" by passing the -S options.)
+importing of "site.py" by passing the -S option.)
 
 Then bang on it until it executes very simple Python statements.