There are 50 employees in the office of ABC company. Of these, 22 have taken an accounting course, 15 have taken a course in finance, and 4 have taken a marketing course. None of the employees has taken exactly two of the courses, and one employee has taken all of these course. How many of the 50 employees have taken none of the courses?

There are 50 employees in the office of ABC company. Of these, 22 have

1.	There are 50 employees in the office of ABC company. Of these, 22 have taken an accounting course, 15 have taken a course in finance, and 4 have taken a marketing course. None of the employees has taken exactly two of the courses, and one employee has taken all of these course. How many of the 50 employees have taken none of the courses?
A.	9
B.	11
C.	12
D.	None of these
Answer» C. 12