Read the following context and choose the best option to answer the question.
Context: One simple little duck the size of his palm took the better part of a half hour for Zack to complete , because his hands could only move so slow , and he stopped frequently to just stare at the folded mess scattered around his crossed legs and the tangled blankets . Messy , messy , he made everything a mess . And then he 'd paused again , losing the battle against self pity as his blank eyes stared at the six paper ducks around him . No , no , no . That was bad , he was n't supposed to think about that .
Question: Why is Zack having difficulties building the paper duck ?
Options: 
A. None of the above choices .
B. Zack does not like this activity and is sulking on his bed .
C. Zack is impatient and can not follow the instructions .
D. Zack is sick and can not move his fingers with dexterity . .


D