He gives his harness bells a shake 
To ask if there is some mistake. 
The only other sound’s the sweep 
Of easy wind and downy flake. 
The woods are lovely, dark and deep, 
But I have promises to keep, 
And miles to go before I sleep, 
And miles to go before I sleep.
Who has promises to keep in the passage from "Stopping by Woods on a Snowy Evening" by Robert Frost?
A.The horse shaking his harness
B.The anonymous speaker
C.The man who owns the woods
D.The poet, Robert Frost
thank you.