Study the given diagram carefully and answer the question. The numbers in different sections indicate the number of persons. What does region '11' represents?
1
The number of Engineers who are singers and jobholders as well as leaders.
2
The number of Engineers who are jobholders and singers but not leaders.
3
The number of Engineers who are only singers and neither jobholders nor leaders.
4
The number of Jobholders who are only Engineers.