Reflex action involves

Which of the following is an example of a reflex action that occurs without our conscious awareness?

One common example of a simple reflex is:

The phenomenon where the mouth becomes watery upon looking at delicious food is due to:

In reflex action, the reflex arc is formed by:

Which sentences are $WRONG$ about acquired reflex action?
$I$. These are non-heritable.
$II$. These are permanent.
$III$. They may disappear or re-appear.
$IV$. Example is knee jerk.