Option b is the correct answer. Chronological sequence of visitors Megasthanes: Megasthenes, an ancient Greek historian and diplomat, arrived in India during the reign of Chandragupta Maurya, around 300 BCE approximately. He visited Pataliputra, capital of the Mauryan Empire, and compiled his observations in the lost work "Indica." He described Indian geography and mentioned interactions with King Sandracottus (Chandragupta Maurya) and even possibly with King Porus during Alexander the Great's invasion. Fa-Hien: Faxian ( 337 C E − c .422 C E 337CE−c.422CE ), also known as Fa-Hien, was a Chinese Buddhist monk and traveler who journeyed from China to India between 399 and 412 CE to obtain Buddhist texts. He spent a decade in India during the reign of Chandragupta II. His travelogue, "A Record of Buddhist Kingdoms," provides valuable insights into early Indian Buddhism. Faxian visited sacred Buddhist sites and monasteries, including Kapilvastu, Bodh Gaya, Varanasi, and Kushinagar. He described the prosperity of Indian cities and their inhabitants' devotion to Buddhism. Hieun-Tsang: Hieun-Tsang, born in AD 602, embarked on a journey to India in 629 during the Tang Dynasty. He traveled through perilous terrains and visited various Indian cities. He admired King Harsha Vardhan's patronage of Buddhism in Kannauj. After 16 years, he returned to China in AD 645, translating Buddhist texts until his death in AD 664. I-Tsing: Chinese Buddhist traveler I-Tsing journeyed to India from 671 to 695 A.D. His travelogue 'Record of the Inner Law sent home from the Southern Sea' documents customs, daily life, and Buddhism's schools. This valuable book translates his entire travelogue, offering insights into Buddhism and I-Tsing's experiences, along with a general introduction to the religion.