Distance/Correspondence MCA

Yes, there is an entrance test for admission in distance MCA.

As per the AICTE notification (advertisement no. UB/04 (03)/2010), universities do not require prior approval of AICTE to commence a new department or course and programme in technical education. For running, conducting technical courses/programs approval of AICTE is not necessary, However, universities have the obligation to conform to the standards and norms laid down by the AICTE (reference Hon'ble Supreme Court of India for the interpretation of the provisions of the AICTE Act in the matter of Bharathidasan University vs. AICTE and others).

There is no correspondence MCA course provided by Kuvempu University. Fee for regular MCA course is Rs. 28000 per year.

Hello dear,
There are lots of universities offering MCA in distance mode like Amity, Manipal and open universities like IGNOU, Bhoj Open University, etc.
Average fees for distance MCA is between 15000 to 1 lakh.

Regarding the subject in UGC NET entrance exam, I am afraid its not going to be your choice. You can appear only for the Computer Science and Application and that is the end of the story. The subject is selected based on the post graduation qualification. Not the graduation course that you have taken.
Therefore you can not select between Maths and Computer Science. Your post graduation degree is Master of Computer Applications therefore the subject will be Computer Science and Applications.
Regards.