When the Author of the Textbook, Laurence Steinberg, Says That

When the author of the textbook, Laurence Steinberg, says that "Some researchers have argued that the question of whether self-esteem is stable during adolescence is a poor one," what does he mean?

A) Researchers have argued that asking whether self-esteem is stable is a poor question because it is impossible to measure self-esteem, let alone measure whether it changes during adolescence.
B) Researchers have argued that asking whether self-esteem is stable is a poor question because self-esteem does not change across development; self-esteem is one of the most stable traits.
C) Researchers have argued that asking whether self-esteem is stable is a poor question because group averages often hide substantial differences between people.
D) Researchers have argued that asking whether self-esteem is stable is poor because the answer is incredibly obvious and, as a result, it does not deserve any more scientific research.