No person shall be appointed as a corrections officer of any county correctional institution unless that person:
a. Is a citizen of the United States;
b. Is able to read, write and speak the English language well and intelligently and has a high school diploma or its equivalent;
c. Is sound in body and of good health;
d. Is of good moral character;
e. Has not been convicted of any offense which would make him unfit to perform the duties of his office.