If you'll be presenting to an audience that doesn't know you,

A) there isn't much you can do to build your credibility.
B) present your qualifications at the end of your talk.
C) build your credibility as you deliver your presentation.
D) introduce yourself and note your relevant experience and accomplishments.

Credibility

The quality of being trusted and believed in, often based on a reputation for honesty, reliability, and expertise.

Relevant Experience

Work or activities that directly relate to the position or field one is applying to or working in.

Accomplishments

Achievements or completed goals that are often used to demonstrate an individual's capabilities or successes.