[求助]一道GWD求解

snowflowers

GWD23-Q30：

There are 8 books on a shelf, of which 2 are paperbacks and 6 are hardbacks.  How many possible selections of 4 books from this self include at least one paperback?

A. 40
B. 45
C. 50
D. 55
E. 60

答案选的C，但我觉得应该选D。不知各位nn怎么认为？？？谢谢指点！！！

snowflowers

thanks !!!!!!!!!!