The correct answer is option 4, which states that the Gypsies are regarded as of Indian origin because their language, called Romani, is an Indo-Aryan language, and they believe that they came from India.
Option 1 states that the Gypsies are regarded as of Indian origin because they follow Indian religious practices. However, this is not the main reason for their classification as being of Indian origin.
Option 2 correctly states that the Gypsies are regarded as of Indian origin because their language, Romani, is an Indo-Aryan language. This linguistic connection provides evidence of their Indian origin.
Option 3 states that the Gypsies are regarded as of Indian origin because they believe that they came from India. While their belief is a contributing factor, it is not the only reason why they are considered to have originated from India.
Option 4 combines the correct answers from options 2 and 3. The presence of the Romani language and their belief in their Indian origin are the key reasons why the Gypsies are regarded as being of Indian origin.
Therefore, option 4 is the correct answer.