"Sufficient and Necessary" is not a particular question type. Instead, it's a concept that shows up in a variety of LR question types -- most often MBT, Principle, Strengthen w/ Sufficient, and the Parallel questions. "S & N" also sometimes shows up in EIR and Strengthen w/ Nec too.
So yes, this is a EIR question, but it's classified as S&N because it tests that concept.
