With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: The information available on Greek fire is exclusively indirect, based on references in the Byzantine military manuals and a number of secondary historical sources such as Anna Komnene and Western European chroniclers, which are often riddled with errors. In her "Alexiad", Anna Komnene provides a description of an incendiary weapon, which was used by the Byzantine garrison of Dyrrhachium in 1108 against the Normans. It is often regarded as an at least partial "recipe" for Greek fire:This fire is made by the following arts: From the pine and certain such evergreen trees, inflammable resin is collected. This is rubbed with sulfur and put into tubes of reed, and is blown by men using it with violent and continuous breath. Then in this manner it meets the fire on the tip and catches light and falls like a fiery whirlwind on the faces of the enemies. At the same time, the reports by Western chroniclers of the famed "ignis graecus" are largely unreliable, since they apply the name to any and all sorts of incendiary substances.
text_B: Is the available information on Greek fire trustworthy?
NO.