Final answer:
Issue-specific messages, authenticity, and simplification would be the most appropriate message execution style for ads of Martha Stewart's campaign.
Step-by-step explanation:
The most appropriate message execution style for ads of Martha Stewart's campaign would be a combination of issue-specific messages, authenticity, and simplification. Issue-specific messages and responses that can be presented as '30-second sound bites' or campaign slogans would allow for easy understanding and memorability. Authenticity, as seen in George Bush's advertisements, can create a sense of trust and credibility. Finally, simplifying the campaign message to make it easy to understand and resonate with potential supporters would be crucial.