why might an author use an allusion in writing?

a. to make the reading more personal
b. to make the reading more difficult
c. to add a figure of speech
d. to add layers of meaning

d. to add layers of meaning

By using an allusion, an author can refer to a well-known person, event, or literary work in order to add depth and complexity to their writing. This can provide readers with additional layers of meaning and context, enriching the overall reading experience.