This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
A 3 year old child can do all, except – 
Select and explain. 
A. Eat with a spoon, B. Climb stairs running, C. Walk properly, D. Vocabulary of 20–100 words
B: Climb stairs running
Answer: B: Climb stairs running 
Explanation: Important milestones of a 3 years child

Rides tricycle                                                             
Stands momentarily on one foot.                           
Draws a circle.                                                            
Can dress or undress himself completely              
Builds tower of 10 cubes 
Knows his age and sex.      
Repeat a sentence of 6 syllables        
Has a vocabulary of 250 words.                 
Counts 3 objects correctly.    
Can withhold and postpone bowel movement.