Final answer:
The appearance of Halley's Comet in the Bayeux Tapestry signified a disaster and William's desire for power during the Norman invasion of England in 1066.
Step-by-step explanation:
In the Bayeux Tapestry, the appearance of Halley's Comet holds historical significance as an omen during the Norman invasion of England in 1066. The passing overhead of the comet was seen as a sign by both sides involved - the Normans and the Anglo-Saxons.
The presence of Halley's Comet symbolized the belief in supernatural forces and divine intervention in medieval times. It added an element of mysticism to the narrative depicted in the tapestry and reflected the anxieties and hopes of the people involved in the conflict.
Therefore, option b: 'It symbolizes a disaster and William's desire for power' is the most accurate description of the historical significance of the Messengers Signal the Appearance of Halley's Comet in the Bayeux Embroidery.