The correct option is this: THE DEER DID NOT PICK UP THE WRITER'S SCENT.
Deer, like most animals has very sharp nose and can easily tell when man or danger is lurking around. For the animals to perceive the presence of an enemy, the wind must blow from the direction of the enemy and carry the scent of the enemy to the animal. But in the passage given above, the wind was blowing away from the direction of the writer, so his scent was not carried to the deer, that is why the writer said the wind is right; the wind direction was favorable to him.