user: Question: What is the release date of the 6 MB L3 cache with the part number BY80607005259AABX80607I7740QM?
Columns: ['Model number', 'sSpec number', 'Frequency', 'Turbo', 'Cores', 'L2 cache', 'L3 cache', 'I/O bus', 'Mult.', 'Memory', 'Voltage', 'Socket', 'Release date', 'Part number(s)', 'Release price ( USD )']
Types: ['text', 'text', 'text', 'text', 'real', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Core i7-720QM', 'SLBLY(B1)', '1.6 GHz', '1/1/6/9', 4.0, '4 × 256 KB', '6 MB', 'DMI', '12×', '2 × DDR3-1333', '0.65–1.4V', 'SocketG1', 'September 2009', 'BY80607002907AHBX80607I7720QM', '$364']
SQL:

assistant: SELECT "Release date" FROM "Table" WHERE "L3 cache" = '6 MB' AND "Part number(s)" = 'BY80607005259AABX80607I7740QM';