“La Belle Dame sans Merci: A Ballad” by John Keats

O, what can ail thee, knight-at-arms,
Alone and palely loitering?
The sedge has withered from the lake,
And no birds sing.

O what can ail thee, knight-at-arms,
So haggard and so woe-begone?
The squirrel’s granary is full,
And the harvest’s done.

I see a lily on thy brow,
With anguish moist and fever-dew,
And on thy cheeks a fading rose
Fast withereth too.

I met a lady in the meads
Full beautiful—a faery’s child,
Her hair was long, her foot was light,
And her eyes were wild.

I made a garland for her head,
And bracelets too, and fragrant zone;
She looked at me as she did love,
And made sweet moan.

I set her on my pacing steed,
And nothing else saw all day long,
For sidelong would she bend, and sing
A faery’s song.

She found me roots of relish sweet,
And honey wild, and manna-dew,
And sure in language strange she said—
“I love thee true.”

She took me to her elfin grot,
And there she wept and sighed full sore,
And there I shut her wild wild eyes
With kisses four.

And there she lullèd me asleep,
And there I dreamed—Ah! woe betide!—
The latest dream I ever dreamt
On the cold hill side.

I saw pale kings and princes too,
Pale warriors, death-pale were they all;
They cried—“La Belle Dame sans Merci
Thee hath in thrall!”

I saw their starved lips in the gloam,
With horrid warning gapèd wide,
And I awoke and found me here,
On the cold hill’s side.

And this is why I sojourn here,
Alone and palely loitering,
Though the sedge is withered from the lake,
And no birds sing.

Source: Keats, John. “La Belle Dame sans Merci: A Ballad.” Poetry Foundation. Poetry Foundation, n. d. Web. 24 June 2011.

Which of the following describes the meter of this poem best?

blank verse
trochaic
free verse
iambic