diff --git a/util-linux/umount.c b/util-linux/umount.c
index a6405df..b45cd8a 100644
--- a/util-linux/umount.c
+++ b/util-linux/umount.c
@@ -81,8 +81,8 @@
 }
 #endif
 
-/* ignored: -v -t -i */
-#define OPTION_STRING           "fldnra" "vt:i"
+/* ignored: -c -v -t -i */
+#define OPTION_STRING           "fldnra" "cvt:i"
 #define OPT_FORCE               (1 << 0) // Same as MNT_FORCE
 #define OPT_LAZY                (1 << 1) // Same as MNT_DETACH
 #define OPT_FREELOOP            (1 << 2)