भारतीय शास्त्रीय संगीत के अनुसार 'नाद' की मुख्य रूप से कितनी विशेषताएँ (गुण) होती हैं?

Which of the following is a major tradition of Indian classical music that originated and developed primarily in Northern India?

Bharat Ratna awardee Pandit Bhimsen Joshi was a leading exponent of which musical gharana?