Subject: mathqa
Question: of 30 applicants for a job , 16 had at least 4 years ' experience , 21 had degrees , and 5 had less than 4 years ' experience and did not have a degree . how many of the applicants had at least 4 years ' experience and a degree ?
Option: 
A: 12
B: 7
C: 10
D: 9
Answer: A