The opposite of an astute person is a
a. liar.
c. weakling.
b. dimwit.

The answer is: dimwit.

An astute person would be considered someone who can produce the right circumstances by his or her own means to achieve a desired and projected goal or objective. On the opposite side, one would find a dimwit, which is a person of a slow, deficient or short mental capacity or intelligence that would be an easy prey of circumstances, especially difficult ones.  

citizens are given 25 years of life to prove their worth to society; if they fail to do great things

the objective should be switched