The correct answer is option 4, Guru Granth Sahib. The Guru Granth Sahib, also known as the Adi Granth, is the holy scripture of the Sikh religion. It is considered the eternal guru and contains the teachings of Sikh gurus as well as other spiritual writings from various saints and poets. The Guru Granth Sahib is written in Gurmukhi script, which is the Punjabi language written in a specific script. Therefore, option 3, Gurmukhi, refers to the script in which the Guru Granth Sahib is written, not the holy book itself. Option 1, BhagwadGita, is a Hindu scripture and is not related to the Sikh religion. Option 2, Baani, is a term that means divine word or divine hymns and can refer to the hymns found in the Guru Granth Sahib, but it is not the name of the holy book itself.