An allusion is a reference to a well-known person, place, event, literary work, or work of art.
In this case, the example that contains an allusion is:
His beard curled in long ringlets, reminiscent of Michelangelo's Moses.
This refers to the famous sculpture of Moses by Michelangelo, which is a well-known work of art. The other options contain similes or metaphors but do not reference a broader cultural or historical context.