Why doesn't the following construction work in ms sql?

Question

SQL Server

I can't figure out why people are complaining about this design.

select b from table 
where c in (select c1 from table2) and not in (select c2 from table3)

underlines the second in , the number of columns and their type are the same

Answer 1

select b from table 
where c in (select c1 from table2) and c not in (select c2 from table3)