Questions 14 to 16 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions. Now listen to the passage. In what way are the open prisons different from the closed prisons

A．Some of their prisoners are allowed to study or work outside prisons.
B．Most of their prisoners are expected to work.
C．Their prisoners are often sent to special centers for skill training.
D．Their prisoners are allowed freedom to visit their families.