For What Reason Have Insurance Carriers Seen a Reduction in the Use

For what reason have insurance carriers seen a reduction in the use of dental amalgam for posterior restorations by approximately 45% in the past 20 years?

A) Other direct restorative materials have superior durability,ease of handling,and physical characteristics.
B) Its wear resistance and compressive strength are inferior to composite resin and glass ionomer cement.
C) A study conducted by the National Institutes of Health (NIH) in 1991-1993 concluded that amalgam is not safe for human use.
D) Concerns by patients about its safety and its lack of esthetics have prompted many patients to request tooth-colored materials.