The intended meaning is that
the society(i.e., its members collectively) needs to reconsider
its priorities on education and national defense in context with the background information given in first part of the sentence.
society is singular so 'its' is correct usage 'their' is incorrect - option D is out
(A) society to reconsider its priorities regarding - clear and concise construction - correct.
(B) society’s members to reconsider
the priorities of - distorted meaning - Incorrect
our society's members - awkward - we can say our society because we are part of it but can we say our members?
(C) society to reprioritize the value of - distorted meaning -are we going to reprioritize the value of education and national defense - Incorrect
(E) society to reconsider whether to prioritize - distorted meaning - aim is to reprioritize education and national defense and not to decide whether to prioritize or not - Incorrect
Answer A