Final answer:
Without additional context, the usefulness of Ada's skills as a cook and a seamstress for her career cannot be determined. In the case of Ada Lovelace, such skills would be unrelated to her work in computing. Moreover, all the listed inventions were successful during their respective eras.
Step-by-step explanation:
The usefulness of Ada's skills as a cook and a seamstress in her career and life cannot be determined without more context. These skills could potentially be highly useful in a variety of situations, especially if Ada found herself in a position where self-sufficiency was important, or if she chose a career path that valued these practical skills. However, without specific information about Ada's career and the demands it placed on her, it is impossible to accurately assess the utility of her cooking and sewing skills.
If the question pertains to Ada Lovelace, known for her work on Charles Babbage's early mechanical general-purpose computer, the Analytical Engine, then those domestic skills would be largely unrelated to her contributions to computing. So, in the case of Ada Lovelace, the answer would be A) Not useful at all, but since the Ada in question is not clearly identified, the correct answer here is D) Cannot be determined.
Regarding the principal's emphasis on personal experience, it's difficult to assess without context. Personal experiences can shape a teacher's approach and relatability to students, but they don't necessarily reflect on their academic ability or subject knowledge.
As for the inventions of the era, all the options listed, A) high-powered sewing machines, B) movies with sound, C) frozen foods, and D) typewriters, were successful inventions of that time.