user: Question: What was the album Closer: The Best of Sarah McLachlan certified as?
Columns: ['Rank', 'Artist', 'Album', 'Peak position', 'Sales', 'Certification']
Types: ['real', 'text', 'text', 'text', 'real', 'text']
Sample row: [1.0, 'Nickelback', 'Dark Horse', '1', 480000.0, '6x Platinum']
SQL:

assistant: SELECT "Certification" FROM "Table" WHERE "Album" = 'Closer: The Best of Sarah McLachlan';