A Difference Between Maslow's Need Hierarchy and Alderfer's ERG Theory

A difference between Maslow's need hierarchy and Alderfer's ERG theory is that

A) Maslow's theory states several needs can be satisfied at the same time, whereas Alderfer's ERG theory follows a specific structure.
B) Maslow's hierarchy has scientific validity, whereas Alderfer's ERG theory has not been scientifically supported.
C) Maslow's needs theory has general applicability, whereas Alderfer's ERG theory aims at understanding people's needs at work.
D) Alderfer's ERG theory focuses on five levels of needs, whereas Maslow's theory focuses only on three needs.
E) Alderfer's ERG theory is popular among American managers, whereas Maslow's theory is not.