What is the figure of speech that has been used on the following phrase" intellectually impoverished " ?

How can behavioral science be applied in improving public health? a. by tracking a disease to determine its sourceb. by creating promotions that improve health habitscboth by tracking a disease to determine its source and by creating promotions that improve health habitsd. neither by tracking a disease to determine its source or by creating promotions that improve health habits

Which of these sentences uses parallel structure

Which statement correctly analyzes how the passages work together to create a central idea?