What is the purpose of the text A: To give us a portrait of a legendary person—Abram Petrovich Gannibal. B: To reveal the origin of Gannibal. C: To indicate the connection of Pushkin and Gannibal. D: To introduce Hugh Barnes's research work and his book on Cannibal.

文献：Guiding of terawatt laser pulses in preformed plasma channels. Nikitin, Sergei Petrovich (Univ. of Maryland, College Park, MD, USA). 160 pp. Avail. UMI, Order No. DA9925820 From: Diss. Abstr. Int., B 1999, 60(4), 1682 (English) 1999.以下说明正确的是：