As per Dharamsutras and Dharmashastras, which of the following were the functions of Brahmanas?

All of these

The Dharmasutras and Dharmashastras also contained rules about the ideal “occupations” of the four categories or varnas. Brahmanas were supposed to study and teach the Vedas, perform sacrifices and get sacrifices performed, and give and receive gifts. Kshatriyas were to engage in warfare, protect people and administer justice, study the Vedas, get sacrifices performed, and make gifts. The last three “occupations” were also assigned to the Vaishyas, who were in addition expected to engage in agriculture, pastoralism and trade. Shudras were assigned only one occupation – that of serving the three “higher” varnas.