What was Grace's greatest ambition?

Grace's greatest ambition being to start an aromatherapy clinic suggests that she had a specific passion for holistic healing and wellness. This choice indicates a clear career goal that aligns with an interest in alternative medicine, which often requires not only knowledge but also dedication to learning and a desire to help others through natural therapies.

In the context of the other options, while becoming a doctor, traveling internationally, and writing a book are all valid and admirable ambitions, they may not capture the same level of specific interest or commitment to a particular field as the ambition to start an aromatherapy clinic. This distinction is important in understanding Grace’s motivations and aspirations. Being involved in aromatherapy signifies a personal and perhaps transformative journey that she aspires to share with others, making it a deeply rooted ambition rather than just a career or travel goal.