Nikon D300 - Manual (Page 283)

257
U
Reset Shooting Menu
Choose whether to restore default settings for the current
shooting menu bank. See page 401 for a list of default settings.
With the exceptions of image quality, image size, white balance,
and ISO sensitivity, shooting menu settings are not reset when a
two-button reset (pg. 182) is performed.
Option Description
Yes Restore defaults for the current shooting menu bank.
No (default) Exit without changing shooting menu settings.