Answer:
C.It reinforces the responsibility of the soldiers to obey orders.
Step-by-step explanation:
According to the given question, the effect of the repetition of "NOT" in stanza 2:
"Theirs not to make reply
"Theirs not to reason why", is that it reinforces the responsibility of the soldiers to obey orders.
This is because, the use of "NOT" is used to show that the soldiers are not allowed to reply or reason why but simply to follow orders.