Consider the following schema:

Suppliers$($sid: integer, sname: string, address: string

Parts$($pid: integer, pname: string, color: string$)$

Catalog$($sid: integer, pid: integer, cost: real$)$

The Catalog relation lists the prices charged for Parts by Suppliers.

The primary keys are underlined. In Catalog, $$sid$$ is a foreign key referencing $$sid$$ in Suppliers, and $$pid$$ is a

foreign key referencing $$pid$$ in $$Parts$.$

Based on the schema above, write the following query in SQL:

Find the distinct $$sids$$ of suppliers who supply only red parts.