For which two channels in Adobe Journey Optimizer are "Expression fragments" accessible?

The correct answer pertains to the channels of Email and SMS within Adobe Journey Optimizer. Expression fragments are used to personalize and customize messages sent through these channels. They allow marketers to insert dynamic content into communications, such as a recipient's name, preferences, or relevant data, which enhances engagement and improves user experience.

In the context of Email, expression fragments enable the automated insertion of tailored information into the body of emails, making each communication feel more personalized to the recipient. This is crucial for driving engagement and increasing conversion rates as tailored content typically resonates better with audiences.

Similarly, in SMS campaigns, expression fragments play a vital role by allowing real-time personalization of text messages. This can include information such as appointment reminders, promotional offers, or updates that are specific to the user receiving the SMS.

The other options provided do not focus on these specific channels or may mix channels that do not support the use of expression fragments in the same way, thus making them less relevant within the context of this question.