Business hours areused to specify the days and hours when your company's employees work. You can create multiple sets of business hours for different time zones or regions and assign them to users based on their location or function. To meet the requirement of having different business hours for reps on pacific time and eastern time, you need to create one set of business hours per time zone and assign them accordingly.
References: https://help.salesforce.com/s/articleView?id=sf.customize_supporthours.htm&type=5https://help.
salesforce.com/s/articleView?id=sf.customize_supporthours_assign.htm&type=5

Explanation
Record types are a way to assign different page layouts and picklist values to different users based on their business needs. To use two different page layouts for customer and partner accounts, create one record type for each account type and assign them to the appropriate page layouts and profiles. References:
https://help.salesforce.com/s/articleView?id=sf.customize_recordtype.htm&type=5

Section: Volume E