Critical Reasoning

Which of the following most logically completes the argument?
Sviatovin is a medieval Moringian text whose author and exact date of composition are unknown. However, the
events in the life of Prince Sviatov that the text describes occurred in 1165, and in the diagram of Sviatov's
family that accompanies the text his father, who died in 1167, is identified as still living. Thus Sviatovin must have been written between 1165 and 1167, assuming that
(A) the life of Prince Sviatov is notthe subject ofany other medieval Moringian texts
(B) the author of Sviatovin intended it to provide as accurate a report about Prince Sviatov's exploits as
possible
(C) the diagram accurately represents the composition of Sviatov's family at the time Sviatovin was written
(D) Sviatovin is the earliest Moringian text whose composition can be dated to within a few years
(E) Sviatovin was not written by Sviatov's father himself


Please explain how option B is wrong ?
if we negate it , the conclusion will be weakened