Answer:
Perfume Dept?
Explanation:
This is difficult to answer.  Polyester clothing is popular.  Esters are widely used in perfumes.  Shoes will likely have polyester components.  I was first thinking Ester might be in the perfume section, mostly because Mark doesn't know squat about perfumes.  
There is a lot of polyester-based clothing, but since the option specifies Men's clothing I would judge that since men don't often buy shiny clothes, that the best answer is the perfume section.  Esters generally smell pleasant.