C, for 'commission'.
It is occurrence.
carnations
The word reversible itself is ten letters.Another possibility is palindrome.
Breadcrumb is a 10 letter word. Chocoholic is a 10 letter word.
Additional.
Earwigging.
d for deactivate
commission
commission
Swingshift
commission
pedestrian
P
Commission
murphyslaw :)
Commission