I think you've got to provide some kind of question stem/patient history with this type of question. Step 1 most likely won't just give you an image and ask you what's wrong with it. They usually provide a question stem that would help you reach your answer.
But anyway, for this image, I would consider GBM since I see areas of necrosis and hemorrhage and it's pushing across the midline.
And how can you tell it's melanoma mets?? Like does it have a specific pattern or shape or something??