The correct answer is: A girl, in.
The word “stood” indicates that the person is in a stationary position. The word “burning” indicates that the house is on fire. The word “girl” indicates that the person is female. Therefore, the person must be standing inside the burning house.
The other options are incorrect because they do not make sense in the context of the question. Option B, “The girl, on,” is incorrect because it does not specify where the girl is standing. Option C, “A girl, in,” is incorrect because it does not specify which girl is standing inside the house. Option D, “Girl, in,” is incorrect because it does not specify whether the girl is standing or not.