Question

practice it
therapy for severe depression that involves the administration of an electrical shock to the head
electroconvulsive phototherapy (ect)
electroconvulsive dialysis (ect)
electroconvulsive hypnotherapy (ect)
electroconvulsive hydrotherapy (ect)
electroconvulsive therapy (ect)

Explanation:

Electroconvulsive therapy (ECT) is a well - known treatment for severe depression. It involves the administration of an electrical shock to the head. The other options have incorrect suffixes. Phototherapy involves light, dialysis is related to filtering blood (like in kidney failure treatment), hypnotherapy involves hypnosis, and hydrotherapy involves water. None of these are related to the core concept of ECT which is just "therapy".

Answer:

electroconvulsive therapy (ECT)