user: Question: what is the image quality when the multiple sessions is X, the authentication is ✓ and the date is May 15, 2007?
Columns: ['Project', 'License', 'Date', 'Protocol', 'Technology', 'Server', 'Client', 'Web Client', 'Multiple Sessions', 'Encryption', 'Authentication', 'Data Compression', 'Image Quality', 'Color Quality', 'File Transfer', 'Clipboard Transfer', 'Chat', 'Relay', 'HTTP Tunnel', 'Proxy']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['AJAX Remote Desktop Viewer (AjaxRd)', 'Proprietary', 'June 24, 2006', 'Proprietary', 'socket', '✓', 'X', '✓', '✓', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X', 'X']
SQL:

assistant: SELECT "Image Quality" FROM "Table" WHERE "Multiple Sessions" = 'X' AND "Authentication" = '✓' AND "Date" = 'May 15, 2007';