Explanation
To advertise on TV, radio, print, and social under one banner called New Runners and aggregate total statistics for this marketing effort, an administrator should use Parent campaign field on Campaign object. This field allows creating hierarchical relationships between campaigns by specifying one campaign as parent of another campaign. Parent campaigns roll up statistics from child campaigns such as number of leads generated, amount of revenue won etc. For example, an administrator can create four child campaigns for TV, radio, print and social ads respectively and link them to one parent campaign called New Runners using Parent campaign field. Junction object, lookuprelationship, and master-detail relationship are not features related to Campaign object or hierarchy.
References:https://help.salesforce.com/s/articleView?id=sf.campaigns_parent.htm&type=5

Explanation
A validation rule is a feature that allows administrators to define criteria for data entry or import operations and display an error message when those criteria are not met. For example, a validation rule can require users to select a product type or check a needs review box when saving an opportunity by using an OR function that evaluates both fields. If neither field is populated, then the validation rule will prevent users from saving records with an error message. References:
https://help.salesforce.com/s/articleView?id=sf.fields_about_validation_rules.htm&type=5

Explanation
A sales process is a set of stages that an opportunity goes throughas it moves from creation to close. It can be customized by administrators to match different business models or product lines within an org. Creating a new sales process can help Dreamhouse Realty define a different set of stages for its new home concierge offering that is unlike anything the company has offered in the past and follows a different business model.
Creating a quick action, a new approval process, or a new opportunity product are not solutions for creating a customized sales process; they areused for different purposes such as creating records, approving records, or adding products to opportunities.
References:https://help.salesforce.com/s/articleView?id=sf.customize_salesprocess.htm&type=5