Answer: John joined a group that studies astrological signs.
Step-by-step explanation:
Pseudoscience can be define as the practices, concepts, beliefs and statements that are expected and claimed to be both scientific and fact based ,but they are not verified by any experimental procedure or scientific methodology. It may include hypothesis which is never proved by the evidences.
Astrological science is fact based pseudoscience. As it is based on the beliefs of the planetary motions and their impacts over the human life and the studies may include a hypothesis but cannot be proved by the experimental procedures.
Therefore, on the basis of the above explanation, John joined a group that studies astrological signs. is the correct option.