Steve Is Managing Several Google AdWords Account for His Clients

Steve is managing several Google AdWords account for his clients. Steve would like a way to prevent his clients' ads from showing on his network. What tool can Steve use, to prevent his clients' ads from appearing?

A) Steve can use the 'IP Address Exclusion Tool' option in Account Manager.
B) Steve can't block Google AdWords ads from appearing - he just shouldn't click on them.
C) Steve can use the 'Prevent Ads from Displaying to Me' option in Account Manager.
D) Steve can use the 'Don't Show My Clients' Ads' feature in Account Manager.