Final answer:
The excerpt that contributes to the mood of the story is 'We passed through a range of low arches, descended, passed on, and descended again, arrived at a deep crypt.'
Step-by-step explanation:
The excerpt from 'The Cask of Amontillado' that contributes to the mood of the story is:
'We passed through a range of low arches, descended, passed on, and descended again, arrived at a deep crypt.'
This excerpt creates a sense of darkness, mystery, and foreboding, which adds to the overall eerie atmosphere of the story. The use of words like 'low arches', 'descended', and 'deep crypt' suggests a descent into something ominous and unsettling.