The Mahayana sutras are a very broad genre of Buddhist scriptures that the Mahayana Buddhist tradition holds are original teachings of the Buddha. Some adherents of Mahayana accept both the early teachings (including in this the Sarvastivada Abhidharma, which was criticized by Nagarjuna and is in fact opposed to early Buddhist thought) and the Mahayana sutras as authentic teachings of Gautama Buddha, and claim they were designed for different types of persons and different levels of spiritual understanding.
Try to answer this question if possible (otherwise reply "unanswerable"): What teaching was criticized by Nagarjuna?
Sarvastivada Abhidharma