Answer:
Formal.
Step-by-step explanation:
Formal groups can be defined as the groups which are formed deliberately, having defined structure, for a specific purpose and has some official manager or leader. As Jen's department has been assigned the task of developing new flavors for the company's line of soft drinks. In this instance, the department members function as a formal group because they have come together to achieve a certain goal and has certain hierarchy and structure as well. Moreover, the group has also been made by the top level management and therefore its official as well.