One of the best-known playback singers in the Hindi film industry.Sang in over a thousand Bollywood movies and has sung songs in over twenty regional Indian languages, but primarily in Hindi. Received the Bharat Ratna. Featured in the Guinness Book of World Records from 1974 to 1991 for having made the most recordings in the world.

Lata Mangeshkar is indeed the correct answer. She was one of the most iconic playback singers in Hindi cinema, recorded thousands of songs across multiple languages, received India's highest civilian honor Bharat Ratna, and held the Guinness World Record for most recordings (1974-1991). A.R. Rahman is a composer, not primarily a playback singer. Rahat Fateh Ali Khan is Pakistani and didn't receive Bharat Ratna. Kishore Kumar, while legendary, didn't receive Bharat Ratna or hold the Guinness record.