Hey, Kunjan. Diploma Courses are said to be equivalent to Class 12. But there are only few colleges who offer BBA course to Diploma Students. Though a lot of private institutes look forward to offer BBA course to Diploma Students but you need to beware from them as they are not legit and harming the career. 

There are few best institutions who offer BBA courses to Dilplma Students:

1. Lovely Professional University: Lovely Professional University is one of the best university for regular as well as distance courses in the field of Management. The admission procedure of BBA course from Lovely Professional University is done on the basis of merit in the qualifying examination. 

Process for Applying at LPU:

1. Register on the official website of LPU (https://www.lpu.in/) and upload all the documents as required. 

2. Once the documents are uploaded, the next process will be the verification round which does not take much time. After the verification is done, you will have to apply for Lovely Professional University-National Eligibility and Scholarship Test (LPU-NEST). LPU-NEST is an online test examination conducted by LPU for admission and scholarship purpose in various departments. 

3. After qualifying the examination, you will be able to take admission in LPU and the scholarship will be given on the basis of marks scored in the Test.

2. Sikkim Manipal University: Sikkim Manipal University is also the most suitable university to pursue Bachelor of Business Administration. The process of admission is done on the basis of marks scored in previous examination. You will be alloated a separate date and time to appear in counselling. There will be 2 round counselling and after that you will be able to take admission at SMU. 

3. S.P. Jain Institute of Global Management: S.P. Jain Institute of Global Management is the best rated Management College located in 4 major citites: Delhi, Mumbai, Singapore and Sydney. The admission for BBA is done on the basis of an Entrance Exam commonly known as SP Jain Entrance Test (SP-JET).

SP-JET Examination covers up the same syllabus followed by many competitive examination like Logical Reasoning, Analytics, Basic Mathematics, English, Intelligencia Questions (IQ). It is an offline examination with a duration of 60 minutes at maximum and the selection will be done on the basis of cut-off list released by the Institution. 

In case more information is required, feel free to mention it. Wish you all the best!