Recent Studies Indicate That Many People Have Never Developed Beyond

Recent studies indicate that many people have never developed beyond the stage of concrete operational thought. Which of the following statements lends support to this hypothesis?

A) Many college students feel unprepared to select a career.
B) Many day-to-day tasks require only concrete operational skill levels.
C) Many adults are unable to solve problems requiring abstract reasoning skills.
D) There is a wide variation regarding when people can solve conservation problems.