Final answer:
The pair of words from the passage that are most similar in meaning are 'secrets' and 'confidences'.
Step-by-step explanation:
The passage from David Copperfield by Charles Dickens describes a scene where the wind is causing a commotion among the elm trees, likening the trees to 'giants who were whispering secrets' and the birds' nests to 'wrecks upon a stormy sea'. Among the word pairs provided, B) secrets and confidences are most similar in meaning, both relating to information that is meant to be kept private or shared only with trusted individuals.