单项选择题

A warm-hearted (热心的) nurse on her first day’s work went near to a patient (病人). He has come to London as a tourist. She asked him if she could do something for him, but he only waved (摇) his hand and said something she could not understand. With a smile she asked him again and he just kept saying the same word but in a very much lower voice (声音) before closing his eyes. She ran to the doctor and repeated(重复) to him the sounds she had heard: "My dear girl," said
the doctor after listening carefully to what she repeated, he was saying, " You are standing on I oxygen pipe (氧气管)!"
What do you think of the nurse in the story She is ______.

A. warm-hearted and strict in her work
B. a new hand and not careful
C. good at her work