Step 1: Sarvāstivādins Overview.
The Sarvāstivādins were a prominent early Buddhist school, recognized for their Abhidharma scholarship.
Step 2: Key Text Identification.
Within their corpus, the Jñāna prasthānam stands as the principal text of the Sarvāstivādin Abhidharma system.
Step 3: Comparative Analysis.
- Dharma saṅgrahaṇī: Attributed to different Buddhist scholastic traditions.
- Vinayapitakam: Focuses on monastic regulations, not specific to Sarvāstivādin Abhidharma.
- Vigraha vyāvartinī: A philosophical treatise by Nāgārjuna, unrelated to Sarvāstivādin.
- Jñāna prasthānam: Correct; it is the central text of Sarvāstivādin Abhidharma.
Step 4: Final Determination.
Therefore, the significant text is Jñāna prasthānam.