Which three standard methods can be used to inject contacts into a journey?

In the context of journey building within marketing automation platforms, the standard methods for injecting contacts into a journey are crucial for ensuring that the right audience is engaged at the right time. Among the choices presented, the method of using a Date-Based Event stands out as an effective technique for introducing contacts into a journey.

The Date-Based Event method allows marketers to set up specific criteria based on dates or timing for when a contact should enter the journey. This is particularly useful for events that are scheduled in advance, such as reminders for anniversaries, birthdays, or other significant dates relevant to the contacts. By injecting contacts based on these criteria, businesses can ensure that their marketing efforts are timely and relevant, significantly enhancing engagement potential.

In contrast, while other methods like Mobile Response Event, Predictive Intelligence Event, and CloudPages Form Submit Event may offer varied functionalities, they do not represent standard methods for injecting contacts in the same explicit way that Date-Based Events do. Their focus is more on responses or submissions rather than on specific, date-driven entry points into a journey. This context highlights why the Date-Based Event is the correct approach for the question posed.