a: People who start up their own business typically come from two extreme backgrounds: One is the business family background and the other is a steady professional family background.
b: Typically, people from different backgrounds face different kinds of basic problems.
c: The people from both the backgrounds find it very difficult to establish and manage an enterprise.
d: Starting up and managing a small business is no joke.

• d b c a

• b a c d

• d a c b

• d a c b