Beethoven, who at first only wanted to study and play the piano, composed some of the most well-known songs of all time. Which phrase is an adjective clause in the sentence?
A)of all time
B)the most well-known
C)who at first only wanted to study and play the piano
D)study and play the piano
An adjective clause is used to describe the subject in more detail. Having that in mind, the correct answer is C) who at first only wanted to study and play the piano.