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: The initial procedure of choice to investigate a possible obstruction of the biliary tract is: 
 Options:  <0> Hepatobiliary ultrasound. <1> Endoscopic retrograde cholangiopancreatography (ERCP). <2> Colangio Magnetic Resonance. <3> Computed tomography. Abdominal CT <4> Percutaneous transhepatic cholangiography.
medicine

Question: The six-membered cyclic ether with an oxygen atom is called: 
 Options:  <0> Oxolane <1> Oxano <2> Dioxane <3> Oxirano. <4> Oxetano.
chemistry

Question: What characterizes the physiological aging process of the musculoskeletal system? 
 Options:  <0> Synovial thinning. <1> Lumbar kyphosis more pronounced. <2> Breakage of the articular surfaces. <3> Shortening of muscular latency and relaxation periods. <4> Decrease in bone connective tissue.

nursery