Explanation:

- The first recipient of the National Award for Best Music Direction was K. V. Mahadevan, an acclaimed music composer in Indian cinema, particularly known for his work in Tamil and Telugu films.

- K. V. Mahadevan was honored for his composition in the Tamil film "Kandan Karunai," which showcases his exceptional ability to blend melody with traditional Indian music elements.

- Vidyasagar is another eminent music director known for his work in Indian cinema, particularly Malayalam and Tamil films. However, he was not the first to receive this award.

- Deva is recognized for his contribution to music in Tamil cinema and has been influential in popularizing gaana songs but does not fit this context.

- Karthik Raja is a contemporary music director known as Ilaiyaraaja's son, making notable contributions in modern Tamil cinema.