Final answer:
The toughest public policy issue confronting the direct marketing industry is likely Invasion of privacy, due to the increasing digitization of personal information and the resulting risks of data breaches and unauthorized information use. The answer is option D.
Step-by-step explanation:
According to the text, the toughest public policy issue now confronting the direct marketing industry is likely D. Invasion of privacy. This issue arises as more personal information is stored digitally, increasing the risk of data breaches and unauthorized use of information.
Governments are also involved, as they regulate access to information to protect residents' safety, potentially infringing on individual privacy rights. High-profile incidents involving retailers like Target and financial institutions like JP Morgan have highlighted the vulnerability of personal information to cyber-attacks.