That depends on your interest.

But note

Automobile is subset of mechanical engineering

Whereas

Mechanical engineering contains all solid, liquid and gas mechanics.

You should always choose a branch according to your interest and passion.

Mechanical branch is one of the oldest and evergreen branch in engineering. Scope of mechanical branch is increasing day by day. It provides good placements as well.

Automobile engineering are for those who are passionate about cars.

If we compare the branches then mechanical engineering have good number of jobs and provides good placements.

You should always try to get admission in good colleges to get good teaching, placements and exposure.

Good Luck!!