People of different persuasions have met on the same platform.

Tastes are the things that someone enjoys or finds pleasant. People of different tastes have met on the same platform when they have come together to share their interests or hobbies.

Qualifications are the skills, knowledge, and experience that someone has. People of different qualifications have met on the same platform when they have come together to work on a project or to learn from each other.

Convictions are strong beliefs that someone holds. People of different convictions have met on the same platform when they have come together to discuss or debate their beliefs.

In this case, the correct answer is D because the question is about people who have come together to discuss or debate their beliefs. These beliefs are their convictions, which are strong beliefs that they hold.