Sometimes I think how grateful I would be today if I had learned

Sometimes I think how grateful I would be today if I had learned more back then about what really matters.
A、I would be happy now if I had learned more about great historic events.
B、I would be satisfied today if I had learned more about things really important.
C、Since I have learned how to deal with difficulties, I feel content with my education.
D、Since I have learned more than other students, I feel thankful to my school teachers.
【正确答案】：B