Final answer:
Mr. Mossel was most likely c)taking the Thematic Apperception Test (TAT), a projective test where ambiguous scenes are used for individuals to project their unconscious thoughts and feelings by storytelling.
Step-by-step explanation:
If a psychotherapist showed Mr. Mossel a series of ambiguous scenes and asked him to make up a story about each, Mr. Mossel was most likely c. taking the Thematic Apperception Test (TAT). The TAT is a projective test where people are presented with ambiguous images and then make up stories to go with the images. This process helps to uncover their unconscious desires, fears, and struggles by allowing them to project their inner thoughts and feelings onto the images. The creation of stories based on these images provides insight into the person's social world, hopes, fears, interests, and goals, while also tapping into their unconscious psychological processes.