The Adi Granth, the scripture of the Sikhs, was compiled in 1604 by:

The Adi Granth, the scripture of the Sikhs, was compiled in 1604 by Guru Arjan Dev, the fifth Sikh Guru.

How the Adi Granth was compiled:

• Guru Arjan Dev collected the hymns of the first four Gurus (Guru Nanak, Guru Angad, Guru Amar Das and Guru Ram Das), along with his own compositions.
• He also included the hymns of other saints and poets, both Hindu and Muslim, whose ideas were similar to those of the Gurus, such as Kabir, Namdev, Ravidas (Raidas), Baba Farid, Sheikh Farid, Surdas and Jaidev.
• The text was written down by Bhai Gurdas, a learned Sikh scholar, in the Gurmukhi script.
• It was installed in the Harmandir Sahib at Amritsar in 1604, with Baba Buddha as its first granthi (custodian).

Features:

• The hymns are arranged according to the ragas (musical modes) in which they are to be sung; there are 31 main ragas.
• It contains the teachings of one God, the remembrance of God's name, equality, humility and service.
• Its language is a mixture of Punjabi, Braj, Hindi, Persian and other languages.

Later development:

• Guru Gobind Singh added the hymns of his father, Guru Tegh Bahadur, to it at Damdama Sahib.
• Before his death in 1708, Guru Gobind Singh declared the scripture to be the eternal Guru; it is now called the "Guru Granth Sahib".
• It has 1,430 pages (angs) in its standard form.

NCERT on the Adi Granth:

• NCERT notes that the compositions of Baba Guru Nanak and his successors, along with those of other saints such as Kabir, Baba Farid, Ravidas and Namdev, were compiled by Guru Arjan in 1604.
• These compositions, called "gurbani", are composed in various languages.

About Guru Arjan Dev:

• He completed the construction of the Harmandir Sahib.
• He was executed in 1606.

Why not the other options?

• ✗Guru Nanak Dev composed hymns but did not compile the Granth.
• ✗Guru Ram Das was the fourth Guru.
• ✗Guru Gobind Singh added his father's hymns later.