Read the following paragraphs and answer the question below. Like many other students beginning graduate school, I was quickly overwhelmed with responsibilities and had to find time for studying by letting go of many other things I valued. Letting go of football and the violin was, however, self-defeating: it might have bought me more time in the short term, but spending that extra time on work only made me more stressed and less productive. Towards the end of my MSc program, I started to lose my motivation and curiosity for science and research, as well as my creativity. Spending so much time and energy in the laboratory, and focusing all my attention on my thesis and courses, made me feel down, lethargic and almost totally uninterested in my field — not to mention short-tempered and oversensitive in my personal interactions. Question: What did the author have to do when starting his graduate school?
A、To study longer time.
B、To stop all his hobbies.
C、To lose motivation for hobbies.
D、To stop being short-tempered.