Please give a $$True$$ or a $$False$$ rating to each statement below. You can add an explanation if you feel the question is ambiguous, but that is option in this part.

a$.$ A schema that is in Third Normal Form $(3$NF$)$ must also be in Second Normal Form $(2$NF$).$

b$.$ A foreign key can contain a NULL.

c$.$ The union rule allows combining functional dependencies A$$CD and A$$EF into a functional dependency A$$CDEF$.$

d$.$ A UNIQUE constraint on a column allows insertion of a NULL.

e$.$ A column that appears in the WHERE clause must always appear in the SELECT clause.

f$.$ SQL query output is always sorted by the primary key.

g$.$ You can never use a WHERE clause and a HAVING clause in the same query.

h$.$ Queries that output the same results will always run at the same speed regardless of how they are written.

i$.$ DISTINCT queries always return a different number of rows than just a SELECT query.