What has been determined to be an effective treatment for insomnia

A)  electroconvulsive shock therapy
B)  cognitive-behavioural therapy 
C)  hypnosis
D)  salt therapy

Insomnia

A sleep disorder characterized by difficulty falling and/or staying asleep.

Cognitive-Behavioural Therapy

A form of psychotherapy that treats problems and boosts happiness by modifying dysfunctional emotions, behaviors, and thoughts.

Electroconvulsive Shock

A medical treatment most commonly used for severe depression, involving electric currents passed through the brain to induce seizures.