Option a is the correct answer. The Chinese general who defeated Kanishka was Pan Chao (also known as Ban Chao). As per the book of the Later Han Dynasty, Hou Hanshu, general Ban Chao fought battles near Khotan with a Kushan army of 70,000 men. He was successful in repelling the Kushans following a scorched-earth policy in 90 AD . He was a prominent diplomat, explorer, and military general of the Eastern Han Dynasty. Ban Chao played a significant role in administering and establishing Han control over the "Western Regions" (Central Asia). He also led Han forces in campaigns against the Xiongnu and re-established Han influence in the Tarim Basin region. Ban Chao's efforts earned him the title of Protector General of the Western Regions.