Design a DW for a large mobile phone provider $$ XYZ$.$ The firm has over $4$million customers based on the phone numbers allotted. Managers at XYZ are interested in analyzing the sales facts on plan and payment related characteristics, which are: a$.$ customer plan type $($contract or no contract$),$ b$.$ credit rating $($low$,$ med, high$),$ c$.$ payment$-$option $($autopay$,$ non$-$autopay$).$ These data can be placed in a junk dimension called Payment$\_$type. The facts of interest are monthly minutes used, monthly data used, monthly phone charges, and monthly data charges for customers. Thus, there are only three dimensions of interest: Customer, Time, and Payment$\_$Type $($a junk dimension$).$ The data warehouse will store data with a span of $4$ years. Note that the facts are stored at the monthly aggregate levels. Thus, there would be only $4$ tables, three dimension tables and one fact table.

A$.$ Make the necessary star schema ERD for this DW $$ showing all the keys $($PKs and FKs$),$ attributes, relationships, etc, given the dimension tables noted above and the fact table requirements. We need only the ERD. Be sure to clearly mark all the relationships and keys. Hand draw neatly or use Lucid charts

B$.$ Make the actual Payment$\_$Type dimension table $($not just the metadata, but show the actual filled in data in a tabular form. Clearly specify what will be the primary key with an underline on the table column$/$s$).$ Make sure the rows are organized in a logical$,$ sequential order. Use the provided file with a blank table

C$.$ How many rows are expected in the time dimension table? State any assumptions clearly.