What keyword is missing in the following line from /etc/fstab in order to make a USB flash device writeable by the user fred when mounted:

What keyword is missing in the following line from /etc/fstab in order to make a USB flash device writeable by the user fred when mounted:

/dev/sda1 /mnt/usbflash vfat defaults,users,______=fred,umask=022, 0 0

(Provide the option name only without any settings)

Answer: uid