Final answer:
The experiment uses a Styrofoam cup with a Lid as a calorimeter, which allows for temperature measurement and mixing with a thermometer and stirrer while providing insulation.
Step-by-step explanation:
The calorimeter being used in the described experiment is d. Styrofoam cup with a Lid. Calorimeters are designed to measure the heat of chemical reactions or physical changes as well as heat capacity. A coffee cup calorimeter typically consists of two polystyrene cups used to hold the reaction mixture, thereby minimizing the loss of heat to the surrounding. An insulated lid with two holes is used to insert a thermometer and a stirrer, which helps in recording the temperature changes and ensuring the mixture is uniform throughout the process. This type of calorimeter, while simple, offers a greater degree of insulation compared to a single cup without a lid or an open beaker, but is still not as accurate as more sophisticated calorimeters used in advanced research.