Final answer:
The word 'enveloped' suggests that Dublin was surrounded by darkness or fog, creating a concealed atmosphere in the city. Option number b is correct.
Step-by-step explanation:
The use of the word "enveloped" in the given context suggests that Dublin, Ireland was completely surrounded or covered by darkness, emphasizing the notion of the city being immersed in the night.
The darkness acts almost like a blanket or covering, emphasizing a sense of concealment and absence of light, except for the dim moonlight. Therefore, the appropriate answer to what the term "enveloped" reveals about the city would be that it was covered by fog or darkness, creating an atmosphere of concealment.