Final answer:
The destruction of the littluns' sand castle may symbolize both the potential destruction of their sense of home and security on the island, as well as the older boys' decreasing morality, suggesting that (d) Both a and b could be possible answers is the most appropriate option.
Step-by-step explanation:
The destruction of the littluns' sand castle by the older boys in Lord of the Flies can symbolize several things. On one level, the sand castle may represent the children's fragile sense of home and security on the island, suggesting that this security may eventually be destroyed, hence answer choice (a) is a possible interpretation. However, the act also reflects the deteriorating morality of the older children and their increasing disregard for the innocence and well-being of the younger ones.
This can symbolize the broader theme of the loss of innocence and the descent into savagery, thus making answer choice (b) another viable interpretation. Therefore, both (a) and (b) could be considered correct answers.