Take into consideration the following schema and write the Relational Algebra

statement for the following:

Manufacturer $($mid$,$ name, address$)$

Supplies $($mid$,$ pid$)$

Parts $($pid$,$ partname, color$)$

a$.$ Find the names of Manufacturers who supply some blue part.

b$.$ Find the mids of Manufacturers who supply some red part and some black part.