A Friend Tells You That Putting a Small Cardboard Pyramid

Multiple Choice

A friend tells you that putting a small cardboard pyramid under your bed as you sleep at night will enhance your "psychic energy" and give you "inner peace." Pseudoscientific claims like this:

A) are irrefutable or nonfalsifiable because they use vague terms like "psychic energy" and "inner peace" and cannot be disproved or tested in any meaningful way.
B) can be tested only using brain-imaging technology such as PET scans, MRI, or fMRI.
C) can be tested only with natural experiments.
D) would be unethical to test because the researcher would have to use a double-blind study.