This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth and development, Subject name: Pediatrics
At 2 years, all the following milestones are achieved except 
Select and explain. 
A. Opens doors, B. Goes upstairs on Alternating feet, C. Climbs on furniture, D. Runs well
B: Goes upstairs on Alternating feet
Answer: B: Goes upstairs on Alternating feet 
Explanation: Emerging patterns of motor behaviour from 1-5years of age15 monthsWalks aloneCrawls upstairs18 monthsRuns stifflySits on small ChairWalks upstairs with one handheldExplores drawers and wastebaskets24 monthsRuns wellWalks up and downstairs, 1 step at a timeOpens doorsClimbs on furnitureJumps30 monthsGoes upstairs on Alternating feet36 monthsRides a tricycleStands momentarily on one foot48 months Hops on one footThrows ball overhandUses scissors to cut out picturesClimbs well60 months SkipsRef: Nelson paediatrics; Table 11-1