What is the purpose of a pentad?
it you generate topics and identify services
it you identify descriptive words for your subject
it you elaborate upon your slogan
it you determine your audience

it helps you elaborate upon your slogan  

Explanation:

A pentad aims to help someone in developing a brand slogan. Usually used in materials and ads. The idea behind the concept of pentad is to create a striking phrase that will be a reference for the brand or product (a film for example), or it will reinforce the memory of the audience of the product.

c.to compare several aspects of the tragedy to other worldwide tragedies

i think the answer is either c or d

im thinking d might make more sense though

sorry if im wrong