Answered

1.Which sentence contains an adjective clause?
  
  A. Pizza, which many people love, can also be nutritious.
  B.Thin-crust pizza with low-fat cheese has fewer calories.
  C.Who ordered deep-dish pizza
  D.Neapolitan pizza, my favorite, usually has a thin crust.



Answer :

Adjective clauses usually start with words like who, which,where and why.I think the sentence you are looking for is A. Adjective clause being "which many people love".