Final answer:
The intensity of the situation and the urgency of staying quiet to not provoke or alert any unseen threats around them further justify why whispering was most appropriate, aligning with option b) Ichabod was frightened of the night.
Step-by-step explanation:
Ichabod Crane whispered to Gunpowder, his horse, likely because he was frightened of the night and the mysterious, unknown dangers it held. In Washington Irving's tale, Ichabod encounters a series of unnerving events that escalate his fear, culminating in a chilling encounter with a headless horseman, believed to be a ghostly apparition.
Ichabod's interactions with Gunpowder throughout the night reflect his growing terror, as he alternates between trying to coax the horse calmly and desperately urging it into a gallop to escape his pursuer. The intensity of the situation and the urgency of staying quiet to not provoke or alert any unseen threats around them further justify why whispering was most appropriate, aligning with option b) Ichabod was frightened of the night.