The correct answer is (a) Guru Amar Das.
The Masand system was a system of religious administration that was started by Guru Amar Das, the third Sikh Guru. Under this system, the Guru appointed a number of Masands, or religious teachers, to spread Sikhism and collect donations from the Sikh community. The Masands were responsible for maintaining contact with the Guru and reporting to him on the progress of their work.
The Masand system was a very effective way of spreading Sikhism and it helped to consolidate the Sikh community. It also helped to ensure that the Guru was kept informed of the needs of the Sikh community.
The Masand system continued to be used by the succeeding Gurus, but it began to decline in the 18th century. This was due to a number of factors, including the decline of the Mughal Empire, which had provided the Sikhs with a measure of protection, and the rise of the Sikh warrior-saints, who challenged the authority of the Masands.
The Masand system was finally abolished by Maharaja Ranjit Singh in the early 19th century.