user: Question: Which country has the Highest mountain of Rettlkirchspitze?
Columns: ['AVE- No.', 'Name', 'Country', 'Highest mountain', 'Height (m)']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['25', 'Rätikon', 'Switzerland Austria Liechtenstein', 'Schesaplana', 2964.0]
SQL:

assistant: SELECT "Country" FROM "Table" WHERE "Highest mountain" = 'Rettlkirchspitze';