Task: Question Answering
Input (English): Question: The afferent neural activity of the peripheral nocioceptors is modulated in the dorsal horn of the marrow, which acts as a door that prevents or does not allow the passage of nerve impulses that come from the nocioceptors and the cortex, refers to? 
 Options:  <1> The peripheral nervous system. <2> The theory of the door. <3> Chronic stress <4> The theory of climbing. <5> The biological process of relaxation.
Output (English): 2