A study of several countries found that rates of major depressive disorder (MDD) and anxiety disorders did not decrease between 1990 and 2015. The main reason for this lack of progress, according to the authors is

	a.	a failure to provide quality care to those in greatest need.
	b.	an increase in environmental risk factors.
	c.	a greater level of public awareness, leading to increased diagnosis.
	d.	an increase in genetic risk factors.