fixes #770 Please correct the typo in the BUILD section
diff --git a/README b/README
index 19d2646..c9559ed 100644
--- a/README
+++ b/README
@@ -46,7 +46,7 @@
 5.  `cmake ..`
     (You can add -DCMAKE_INSTALL_PREFIX=/usr/local or some other directory.)
 6.  `cmake --build .`
-7.  `ctest -G Debug .`
+7.  `ctest -C Debug .`
 8.  `cmake --build . --target install`
     *NB:* This may have to be done as a privileged user.
 9.  (Linux only).  `ldconfig` (As a privileged or root user.)