<span>It changes from melancholy to pleasant. :)</span>
It creates tension when their friendship is tested.
An adjective phrase is a phrase modifying a noun, and in our case the nouns is "Mrs. Cohen" .The whole phrase is: <span>whose cookies are world famous. (answer a); it is an adjective phrase introduced by a pronoun. </span>
If this is a multiple choice question could you list the available answers?