The text is a talk given by the author when______.

单项选择题

In my long life I have seen many changes in our habits and customs and conditions in general. I think that you might be interested if I told you some of them. The world I entered at the age of eighteen when I became a medical student was a world that knew nothing of such advanced things as planes, films, radios or telephones. It was a very cheap world. Prices were stable. When I entered St. Thomas’ hospital I rent a set of rooms in Vincent Square for which I paid 18 shillings a week. My landlady provided me with a very good breakfast before I went to the hospital and a dinner when I came back at half past six. I only had to pay for the breakfasts and dinners twelve shillings a week. For four-pence I lunched at St. Thomas’ on bread and butter and a glass of milk. I could be able to live very well, pay my fees, buy my necessary instruments, clothe myself, and have a lot of fun on fourteen pounds a month. And I could always pawn (当掉) my microscope for three pounds. I spent five years at St. Thomas’ hospital. I was a bad student, for my heart, as you might have guessed, was not in it. I wanted, I had always wanted to be a writer, and in the evenings, after my dinner, I wrote and read. Before long, I wrote a novel called "Liza of Lambeth" , which I sent to a publisher and was accepted. It came out during my last year at the hospital and it was successful. It was of course an accident, but I didn’t know that. I felt I could afford to give up medicine and make writing my profession; so, three days after I graduated from the school of medicine, I left for Spain to write another book. I did not realize, at that time, that I was taking a great risk.

A．he was 18
B．his first novel was published
C．he graduated from the school of medicine
D．he was at an advanced age