Elvira is a UX researcher investigating the needs of humans who are looking for inter$-$state moving services. She invites a participant to the UXR lab and observes them searching the internet for moving services. Elvira instructs the participant to verbalize their thoughts as they search. The participant narrates their process, reactions, and the actions they take as they select a moving service and Elvira takes notes.

What type of study has Elvira conducted? $($According to chapter $4$ of Qualitative HCI Research: Going Behind the Scenes$)?$

Group of answer choices

A diary study

A cognitive walkthrough

A think$-$aloud

A structured interview