The correct statement is "3 only," as Kalidasa is indeed associated with Chandragupta II, a prominent ruler of the Gupta Empire, during whose reign Indian culture and literature flourished. Panini, a renowned grammarian, is attributed to a much earlier period, specifically associated with the 4th to 6th century BCE, predating the Shunga dynasty led by Pushyamitra Shunga. Similarly, Amarasimha, a scholar well-known for his lexicon, is often linked to the earlier Gupta period and not to Harshavardhana, a later historical figure who ruled in the 7th century CE. Thus, only statement 3 accurately reflects historical associations aligned with their specific timelines and contributions to ancient Indian literature.