Betty Trooper Owns and Operates a Realty Company

Betty Trooper owns and operates a realty company. She has provided you with properties.xml, which is a file that contains a list of properties enrolled in the multiple listing database. She has created three different versions of a schema for the properties vocabulary and needs help in choosing the most appropriate schema design for her needs.
-Betty wants to review the Russian Doll design.She understands that there is only one global element with everything else nested inside of it.She also knows that a Russian Doll design is much more compact than a Flat Catalog, but _______

A) multiple levels of nested elements can be confusing
B) it can be more difficult to debug
C) it is easier to debug
D) both a and b need to be considered