In any prosecution under this title for attempt, solicitation, or conspiracy to commit a felony defined by a statute of this state which is not in this title, unless otherwise provided:

(1) If the maximum sentence of imprisonment authorized by law upon conviction of such felony is twenty years or more, such felony shall be treated as a class A felony for purposes of this title;

(2) If the maximum sentence of imprisonment authorized by law upon conviction of such felony is eight years or more but less than twenty years, such felony shall be treated as a class B felony for purposes of this title;

(3) If the maximum sentence of imprisonment authorized by law upon conviction of such felony is less than eight years, such felony shall be treated as a class C felony for purposes of this title.