What is the best method for default selection on multi-select list component?

We are using angular material multi-select component on sign up page.

  1. User can select multiple options from the list of 4-5 whose scope can increase in future. Example : Location A,Location B ,Location C ,Location D

  2. User need to select one location as default selection so that on login, he lands on the corresponding landing page of the location every-time.

How do we go about it ?