Among the following, total number of meta directing functional...

Due to the presence of some groups, the electron density decreases on ortho and para positions. So, the electron density on meta position is relatively higher than ortho and para positions. Thus, these groups directs the electrophilic substitution on meta position.

If the atom attached to the benzene ring contains a pi bond, then the atom containing group acts as meta directing group.
Meta directing groups among the given groups are:

$- {NO}_{2}, - C ≡ N, - COR, - COOH$
are meta directing.