A partial solution to this problem is shown below, where the number 1 indicates when a reviewer is assigned to an applicant. Assign two reviewers to Applicant B and 1 additional reviewer to Applicant C

Applicant
Reviewer A B C
1 X
2 X 1
3 X
4 1
5 X
6 X
7 X
8 1 X
9 X
Demand 2 2 2
Assigned 2

Answer: This is one possible solution. Another is to assign reviewer 9 to applicant C.

Applicant
Reviewer A B C
1 0 0 1
2 0 0 1
3 0 1 0
4 1 0 0
5 0 1 0
6 0 0 0
7 0 0 0
8 1 0 0
9 0 0 0
Demand 2 2 2
Assigned 2 2 2