Forensic entomology is defined as the application of entomology as a field, in the investigation of a crime. Forensic entomologists work a lot with insects, bugs, and arachnids (spiders and such). People working in this field would often provide assistance for law enforcement and medical examiners on a case-by-case basis.
Thus, the best answer for the question is (A) mediocolegal cases involving elderly people dying of natural causes.