Rename the -D option to -Q, to avoid a Jython option name conflict.
diff --git a/Misc/NEWS b/Misc/NEWS
index c082fce..43eff32 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -32,14 +32,14 @@
   this situation, and -Werror::OverflowWarning to revert to the old
   OverflowError exception.
 
-- A new command line option, -D<arg>, is added to control run-time
+- A new command line option, -Q<arg>, is added to control run-time
   warnings for the use of classic division.  (See PEP 238.)  Possible
-  values are -Dold, -Dwarn, and -Dnew.  The default is -Dold, meaning
+  values are -Qold, -Qwarn, and -Qnew.  The default is -Qold, meaning
   the / operator has its classic meaning and no warnings are issued.
-  Using -Dwarn issues a run-time warning about all uses of classic
-  division for int, long, float and complex arguments.  Using -Dnew is
+  Using -Qwarn issues a run-time warning about all uses of classic
+  division for int, long, float and complex arguments.  Using -Qnew is
   questionable; it turns on new division by default, but only in the
-  __main__ module.  You can usefully combine -Dwarn and -Dnew: this
+  __main__ module.  You can usefully combine -Qwarn and -Qnew: this
   gives the __main__ module new division, and warns about classic
   division everywhere else.
 
diff --git a/Modules/main.c b/Modules/main.c
index 3f7b081..f38a5c3 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -29,7 +29,7 @@
 static int  orig_argc;
 
 /* command line options */
-#define BASE_OPTS "c:dD:EhiOStuUvVW:xX"
+#define BASE_OPTS "c:dEhiOQ:StuUvVW:xX"
 
 #ifndef RISCOS
 #define PROGRAM_OPTS BASE_OPTS
@@ -50,15 +50,15 @@
 Options and arguments (and corresponding environment variables):\n\
 -c cmd : program passed in as string (terminates option list)\n\
 -d     : debug output from parser (also PYTHONDEBUG=x)\n\
--D arg : division options: -Dold (default), -Dwarn, -Dnew\n\
 -E     : ignore environment variables (such as PYTHONPATH)\n\
 -h     : print this help message and exit\n\
-";
-static char *usage_2 = "\
 -i     : inspect interactively after running script, (also PYTHONINSPECT=x)\n\
          and force prompts, even if stdin does not appear to be a terminal\n\
+";
+static char *usage_2 = "\
 -O     : optimize generated bytecode (a tad; also PYTHONOPTIMIZE=x)\n\
 -OO    : remove doc-strings in addition to the -O optimizations\n\
+-Q arg : division options: -Qold (default), -Qwarn, -Qnew\n\
 -S     : don't imply 'import site' on initialization\n\
 -t     : issue warnings about inconsistent tab usage (-tt: issue errors)\n\
 -u     : unbuffered binary stdout and stderr (also PYTHONUNBUFFERED=x)\n\
@@ -155,7 +155,7 @@
 			Py_DebugFlag++;
 			break;
 
-		case 'D':
+		case 'Q':
 			if (strcmp(_PyOS_optarg, "old") == 0) {
 				Py_DivisionWarningFlag = 0;
 				break;
@@ -170,8 +170,8 @@
 				break;
 			}
 			fprintf(stderr,
-				"-D option should be "
-				"`-Dold', `-Dwarn' or `-Dnew' only\n");
+				"-Q option should be "
+				"`-Qold', `-Qwarn' or `-Qnew' only\n");
 			usage(2, argv[0]);
 			/* NOTREACHED */
 
diff --git a/Tools/scripts/fixdiv.py b/Tools/scripts/fixdiv.py
index 616622b..175d77b 100755
--- a/Tools/scripts/fixdiv.py
+++ b/Tools/scripts/fixdiv.py
@@ -2,7 +2,7 @@
 
 """fixdiv - tool to fix division operators.
 
-To use this tool, first run `python -Dwarn yourscript.py 2>warnings'.
+To use this tool, first run `python -Qwarn yourscript.py 2>warnings'.
 This runs the script `yourscript.py' while writing warning messages
 about all uses of the classic division operator to the file
 `warnings'.  The warnings look like this: