Which of the following may be the probable cause of the above effect?

• A. There has been a considerable decrease in hiring of engineering graduates due to economic slow-down in the recent years
• B. Students have always preferred to complete graduation in three years time instead of four years for engineering
• C. The Govt. has recently decided to provide post qualification professional training to all engineering graduates at its own cost
• D. There has always been a very poor success rate among the engineering students