An essay about your favorite footwear should analyze the ideas of why you enjoy that specific footwear. Mostly you should analyze the looks and the feel of the footwear, meaning you should discuss why you feel comfortable in the footwear of your choice.
C or d both are good but I am leaning towards c
Essential, both mean something is very important
Id say that the complete predicate would be “have made a decision” and the simple predicate would be “have” or “have made.” Sorry if im wrong. Good luck