What uni choice will give me the best option to get into IB?

Hi, so I'm 19 (turning 20 in June) and I've decided to start uni this Upcoming September after having taken a Gap Year due to the current climate with Covid. One of my greatest ambitions is to get into Investment banking yet as far as I'm aware certain universities (target universities) will give you a better chance of getting into IB, therefore any help or advice with deciding my University choices would be much appreciated.

My choices are as follow:

University of Exeter:

- Mathematics with Economics BSc

University of Bristol:

- Economics BSc

University College London (UCL)

- Management Science BSc

At first, I thought UCL would be the best option due to the fact that it is a very prestigious institution, however, would Management Science itself be considered a strong undergraduate program? However despite Exeter being the weakest institution to say it in a way what really makes me forget that is the fact that I would be doing mathematics which is a really strong degree? 

With all honesty, I'm really lost on what should I decide as my firm option and I really want to make sure that I make the best decision, therefore what do you guys think?

Thanks!