Where do you sit?

What do you sit on when in aero…

a. Ischial tuberosity/ies
b. Ischiopubic ramus/i
c. Pubic bone/s

Edit: Add link to anatomy descriptions.

I never took an anatomy class, so I do not know what those terms mean. But while in aero, on my Cobb Plus, I sit on the nose and use the “pick a side” method from the below link.
http://www.cervelo.com/en/engineering/ask-the-engineers/the-four-and-a-half-rules-of-road-saddles-.html