Choosing a course totally depends on your interest. If you have interest in Agriculture , forestry and geology then you can opt for it. The main comparison is between B.tech and CA as they have good scope in the future with good job options. 

CA- You can join this course if you have analytical mind, your reading habit is updated and you have ability for strategic management.

B.tech- You can join this course if you have technical knowledge and your mathematics is very good. If you have ability to analyse and interpret. You have good communication skill and if you are a team player.

Job Prospect

It is very tough to take admission in top college of engineering. If you are pass out from average college then your starting salary will be around 2 to 3 lakhs but if you clear CA it is sure that you will get a job with minimum salary of 5 lakhs or more.

Before, choosing any course you should keep in mind that it is easy to crack first level of CA that is CPT but it is difficult to crack other levels and in engineering it is tough to get top college but it is easy to complete the course.

Good Luck!!