Answer:
b) To allow him freedom to supply dramatic detail without bringing up questions of how he saw these things, where exactly, et cetera.
Step-by-step explanation:
"Ozymandias" is a well-known sonnet by Percy Bysshe Shelley, published in 1818. This poem reminds us that all power projects - of all times, even today - carry with them a pretense of eternity, expansion and divinization. But for the time being, all this is nothing: it is destined to sink into the sands of forgetfulness. All conflicts and sufferings (as well as joys and passions) will be memories told by some traveler who has crossed his forgotten ruins. The desires of the powerful are nothing more than a naivete of one who believes himself to be eternal. Precisely because of this, the vast majority of empires are linked to God or to the gods, arrogating to themselves the divine desire.
But all these pretensions will always be like the threat of Ozymandias, written on a stone forgotten in the desert: "My name is Ozymandias, and I am King of Kings: Desire, O great Ones, seeing my works!" This is the point of the sonnet's greatest irony, for the traveler who describes the ruins emphasizes both the abandonment of the statues he encountered and the arrogant gaze of Ozymandias sinking in the sand. The traveler does not seem to know who this "King of Kings" would be, and the poem ends by emphasizing the endless solitary sands and the abandonment of the desert.
Shelley decides to tell the story of "a traveler from an ancient land" because so he could provide dramatic and important detail on what the traveler saw without obligation to detail the date, time and where the traveler saw every thing.