Which words in the sentence are the complete adjective clause?
Help me to welcome Mrs. Cohen, whose cookies are world famous.
a. whose cookies are world famous
b. help me
c. to welcome Mrs. Cohen, whose cookies are world famous
d. to welcome Mrs. Cohen
An adjective phrase is a phrase modifying a noun, and in our case the nouns is "Mrs. Cohen" .The whole phrase is: whose cookies are world famous. (answer a); it is an adjective phrase introduced by a pronoun.