In which sentence is a proper noun underlined?

a.
the best produce is sold at wally's market on the corner.

b.
next year, my sister will graduate from duke university.

c.
sally found a gorgeous prom dress at blair's boutique.

d.
that mexican restaurant has the best tacos in town.

Wally's Market

Duke University

Sally, Blair's Boutique

Mexican

Usually proper nouns are capitalized and a name of a person, place or thing. They contrast with common nouns, which are the words for something like boy, dog, city, day etc.

NOUN -- a word (other than a pronoun) used to identify any of a class of people, places, or things ( common noun ), or to name a particular one of these ( proper noun ).

d. cassius cannot believe that a weakling like caesar has become so great.