Question: Among the Production Technicians who are single, how many of them are vendor contact?
SQL: SELECT COUNT(T1.BusinessEntityID) FROM Employee AS T1 INNER JOIN Person AS T2 ON T1.BusinessEntityID = T2.BusinessEntityID WHERE T1.JobTitle LIKE 'Production Technician%' AND T1.MaritalStatus = 'S' AND T2.PersonType = 'VC'