Which are common entry sources to Journey Builder?

The best choice is Audience and entry events because these represent foundational aspects of how individuals or data points are introduced into Journey Builder within Salesforce Marketing Cloud.

Audience refers to the specific group of contacts that have been selected based on defined criteria, allowing marketers to target their messages effectively. Entry events are key triggers that initiate a journey and can include various actions taken by the audience, such as subscribing to a list, completing a form, or engaging with specific content.

These elements are essential for automating the customer journey, ensuring that contacts are engaged based on their behaviors and characteristics. They form the foundation for building targeted marketing strategies and effectively guiding users through tailored experiences based on their interactions.

Other options may involve valid touchpoints or interactions that could be part of a broader marketing strategy, but they do not directly represent the primary mechanisms by which contacts enter and begin their paths in Journey Builder.