Final answer:
The subject is English, and the correct answer is option (a), Mr. Green arrives with an umbrella, as he is described standing at the doorway with an umbrella, implying his arrival.
Step-by-step explanation:
The passage describes a scene in which Mr. Green arrives at a house where Wadsworth, the butler, opens the door for him. Mr. Green stands at the doorway, holding an umbrella and opting not to enter, which portrays him as being anxious and possibly cautious about the situation he is entering. The specific answer to the student's question is option (a), Mr. Green arrives with an umbrella. This can be inferred from the description of Mr. Green holding an umbrella. None of the other options presented match the scene described. Options (b), (c), and (d) are not supported by the given text as they suggest different actions and moods that are not indicated in the scene.