Which statement is not true about a snowflake schema?

a$.$ In a snowflake schema, the data$-$filtering operations related to the dimensions are simplified.

b$.$ Snowflake schema is a type of star schema in which dimension tables can have their own dimension tables.

c$.$ Snowflake schema is a type of star schema in which the fact table can have its own dimension tables.

d$.$ The snowflake schema is usually the result of normalizing dimension tables.