Endorsement of commercial choice (8)
I believe the answer is:
adoption
'endorsement' is the definition.
(I've seen this before)
'commercial choice' is the wordplay.
'commercial' becomes 'ad' (abbreviation for advertisement).
'choice' becomes 'option' (synonyms).
'ad'+'option'='ADOPTION'
'of' is the link.
(Other definitions for adoption that I've seen before include "how to create a family" , "Espousal, a fostering" , "formal selection of candidate?" , "approval" , "Taking-on, acceptance" .)