 
 <prompt> ```Answer dis one:
Wetin be di smallest structural and functional unit of di nervous system?
pick from di following.
[1]. brain
[2]. organ
[3]. neuron
[4]. spinal cord``` <response>: ```[3].```
Translate di text wey dey up to Nigerian pidgin. If there dey programming code inside, leave am as e be. Don't add any extra statement for your response: 