In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.

Question: Hypokalemia is a physiological symptom that can typically occur: 
 Options:  <0> In sleep disorders. <1> In addictions. <2> In anorexia nervosa. <3> In bulimia but not in anorexia nervosa. <4> In disorders of attention deficit and disturbing behavior.
psychology

Question: In which of the drugs with antiviral activity does the purine base called guanine appear? 
 Options:  <0> Lamivudine <1> Zidovudine <2> Ribavirin <3> Acyclovir <4> Didanosine
pharmacology

Question: What is the main cause of functional urinary incontinence in the elderly? 
 Options:  <0> Detrusor instability. <1> Obstruction due to fecalomas. <2> Laxity of the muscles of the pelvic floor. <3> Environmental barriers. <4> Urinary retention induced by medication.

nursery