Which of the following modes of speech delivery would be most suitable for a president addressing Congress or a CEO presenting an annual financial report to stockholders?

The manuscript mode of speech delivery is most suitable for formal and high-stakes situations such as a president addressing Congress or a CEO presenting an annual financial report to stockholders. This approach allows the speaker to deliver a carefully crafted message accurately while maintaining a formal tone and ensuring that all relevant details are included.

In these contexts, precision and adherence to specific language are crucial, as the audience expects a clear and authoritative presentation of important information. Using a manuscript enables the speaker to avoid errors and maintain focus on the key points without the risk of forgetting vital content, which is particularly important when discussing complex subjects like legislative bills or financial data.

Other modes, such as impromptu and extemporaneous, are less suitable in these instances due to their reliance on spontaneity and less structured preparation. While a memorized speech could also be an option, it may lack the flexibility to respond to the audience's reactions or adjust based on the context of the presentation, which can be crucial in such formal settings. Therefore, manuscript delivery is the most effective means of conveying critical information during these important speeches.