Where I code my radar?

Hi guys, I have an easy question.

Where is the best place to put the code to manage my radar (enemy in line of sight ?, in range ?, make noise ?, convert world position to screen position, etc) ?

Option 1 : In MyHUD class, only the client machine will compute stuff and directly display it on the HUD.

Option 2 : In GameMode, the server make the job, and send infos to MyHUD class trough MyPlayerController.

Option 3 : Somewhere else ?

Thanks by advance.