She.
(I'm assuming you did your research and the CTO is in fact female, but it's better to teach people to use a gender neutral term when they don't know the gender of the person in question, and it is irrelevant to the discussion like it is here)
(I'm assuming you did your research and the CTO is in fact female, but it's better to teach people to use a gender neutral term when they don't know the gender of the person in question, and it is irrelevant to the discussion like it is here)