Job can be decided later. First you will have to choose which out of these 3 courses you are good in and you have interest to pursue further.



Because scope wise all 3 are good. Preference you can give to physics if you are good in Maths.



You can do masters course or if you want to do job before it then you will have to decide which field to go in and take internship to gain practical background for all 3.



Good Luck.