I am in class 11 can I prepare for CAT from now onwards and which subjects should I have to select for CAT

CAT offers post graduate courses including MBA and PGDM. First you have to complete your graduation to be eligible for CAT. All graduation courses including B.E. BTech BBA BCom BA etc are accepted by CAT.

Choice of subject in 11th does not make a difference in CAT. However your 12th class score is an important criteria for selection hence I recommend you to focus on that .

All the best!

Hi
CAT or common admission test is a entrance exam for admission into top B Schools in the country. It's for an MBA ie post gradation
If you are in your 11th standard you should be studying for that keeping in mind your 12th standard boards.
You can start praparing for graduation level entrances depending on what you wish to pursue.
Please do not start preparing for MBA. Prepare for graduate level entrances.

Regards