Answer:
Implicit Imputed opportunity cost of time sacrifised while airport drop .
Explanation:
My friend asking me to drop at airport, & paying costs : gas used while driving, parking cost of car - has excluded certain price giving aspects.
He has included all the Explicitly quantified costs , whose payment is made to third person - like fuel & parking.
However, he has not included the implicit cost in terms of opportunity cost i.e other things sacrifised while going to drop him. Such costs payment is although not directly made to third person, but they still reflect a 'cost' as they reflect a gain sacrifised meanwhile.
In this case, it includes time sacrifised while going to drop friend at airport. That time could be used at work, which could have monetary benefits. So, this cost is eliminated to be evaluated by my friend.
