Answer: B. Nicholas was not happy with his aunt for her treatment of him and did not want to help her out.
Step-by-step explanation:
In 'The Lumber-Room’ by Saki, we see a mischievous boy named Nicholas as he tries to out-wit his aunt who had refused him going on a trip with other children because he had refused to eat his breakfast which he claimed had a frog in it.
When she was trapped in the rain-water tank, Nicholas refused to help her out and instead toyed with her to the point of exasperation and still does not let her out because he was unhappy with the way she had treated him.