The correct answer is option 3 - Gandhara art. Taxila was a renowned site for the development and flourishing of Gandhara art. Gandhara art refers to the artistic style that emerged in the Gandhara region, which is present-day Pakistan and Afghanistan, during the period from the 1st century BCE to the 7th century CE. This art style was greatly influenced by Hellenistic and Roman artistic traditions, which is why Gandhara art exhibits a unique blend of elements from both the Greco-Roman and Indian art traditions. The sculptures and reliefs of Gandhara art are known for their realistic figures, dynamic poses, and intricate detailing. The influence of Gandhara art spread throughout the Indian subcontinent and was particularly prominent under the rule of the Kushan Empire.