Website design: what theme should I buy for the best user experience?

We are developing an information system for students and we want to open a website for advertising and explain its functions. But we could not be sure exactly what item we should buy for this purpose.

We remove most of the themes and we have 3 themes now. Could you help us the best for the best user experience for this purpose?


Note: Our clients will be academics from 30 to 60 years old and university managers.

Thank you all for your help guys!