Write SQL query to solve given problem: What time does the business with ID no.12 open on Monday?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T1.opening_time FROM Business_Hours AS T1 INNER JOIN Days AS T2 ON T1.day_id = T2.day_id WHERE T1.business_id = 12 AND T2.day_of_week = 'Monday'