Among the following, who was not a proponent of bhakti cult ?

Nagarjuna was a foundational Mahayana Buddhist philosopher who founded the Madhyamaka school; his work is philosophical-Buddhist rather than part of the medieval Hindu bhakti cult [1]. By contrast, Tukaram belongs to the Marathi abhang tradition of devotional poet‑saints in Maharashtra and is classically identified with the bhakti movement there [2]. Tyagaraja is conventionally counted among the great South Indian composer‑saints whose devotional (bhakti) kritis form a central part of the South Indian bhakti tradition and Carnatic devotional repertoire [3]. Vallabhacharya (Vallabha) founded the Pushtimarg devotional tradition and is a noted exponent of saguna bhakti. Hence Nagarjuna (option 1) was not a proponent of the bhakti cult.

Sources

1. [1] https://iep.utm.edu/nagarjun/
2. [2] History , class XI (Tamilnadu state board 2024 ed.) > Chapter 13: Cultural Syncretism: Bhakti Movement in India > Namadeva > p. 194
3. [3] History , class XI (Tamilnadu state board 2024 ed.) > Chapter 13: Cultural Syncretism: Bhakti Movement in India > 13.2 Spread of Bhakti Movement to the North India > p. 192