Solve the following sql problem:
What is the id of the criteria "Citations Rank"?

Schema:
SCHEMA:
- Table: country
  - Column: id
    - Samples: [1, 2, 3, 4, 5]
  - Column: country_name
    - Samples: [Argentina, Australia, Austria, Bangladesh, Belarus]
- Table: ranking_system
  - Column: id
    - Samples: [1, 2, 3]
  - Column: system_name
    - Samples: [Times Higher Education World University Ranking, Shanghai Ranking, Center for World University Rankings]
- Table: ranking_criteria
  - Column: id
    - Samples: [1, 2, 3, 4, 5]
  - Column: ranking_system_id
    - Samples: [1, 1, 1, 1, 1]
  - Column: criteria_name
    - Samples: [Teaching, International, Research, Citations, Income]
- Table: university
  - Column: id
    - Samples: [1, 2, 3, 4, 5]
  - Column: country_id
    - Samples: [73, 73, 73, 72, 73]
  - Column: university_name
    - Samples: [Harvard University, Massachusetts Institute of Technology, Stanford University, University of Cambridge, California Institute of Technology]
- Table: university_ranking_year
  - Column: university_id
    - Samples: [1, 5, 2, 3, 6]
  - Column: ranking_criteria_id
    - Samples: [1, 1, 1, 1, 1]
  - Column: year
    - Samples: [2011, 2011, 2011, 2011, 2011]
  - Column: score
    - Samples: [100, 98, 98, 98, 91]
- Table: university_year
  - Column: university_id
    - Samples: [1, 5, 2, 3, 6]
  - Column: year
    - Samples: [2011, 2011, 2011, 2011, 2011]
  - Column: num_students
    - Samples: [20152, 2243, 11074, 15596, 7929]
  - Column: student_staff_ratio
    - Samples: [8.9, 6.9, 9.0, 7.8, 8.4]
  - Column: pct_international_students
    - Samples: [25, 27, 33, 22, 27]
  - Column: pct_female_students
    - Samples: [None, 33, 37, 42, 45]

SELECT id FROM ranking_criteria WHERE criteria_name = 'Citations Rank'