Explanation:

• Amir Khusrau was a mystic, philosopher, musician and litterateur who enjoyed the patronage of seven successive sultans during the volatile period of the Delhi Sultanate. Along with Sadi, Nizami and Firdausi, Khusrau is acknowledged as one of the four great pillars of 14th-century Persian literature. He was awarded the title of Tuti-e-Hind, Nightingale of India. He was the disciple of the Sufi saint Hazrat Nizamuddin Auliya. Hence, statement 1 is correct.
• Amir Khusrau played a key role in the evolution of Hindustani classical music. Several musical compositions set in qawwali, khayal, tarana and naqsh, as well as several ragas are attributed to Khusrau. The invention of the table and sitar is also attributed to him. Influenced by the spiritual philosophy of Hazrat Nizamuddin, Khusrau believed in affection and harmony between people belonging to different faiths and creed. He introduced many new ragas such as Ghora and Sanam. He evolved a new style of light music known as Qawwalis by blending the Hindu and Iranian systems. Hence, statement 2 is correct. The invention of Sitar is also attributed to him.
•  He also wrote a number of poems. He experimented with several poetical forms and created a new style of Persian poetry called Sabaq-i-Hind or the Indian style. Hence, statement 3 is correct.
•  He also wrote some Hindi verses. His Khazain-ul-Futuh speaks about the Alauddin's conquests. His famous work, the Tughlaq Nama deals with the rise of Ghiyasuddin Tughlaq.
• Amir Khusro saw the rule of seven Sultans (Balban, Muhammad, Cakubad, Jalaluddin Khilji, Alauddin Khilji, Mubarak Shah Khaliji, Gaisuddin Tughlaq)