Beethoven, who at first only wanted to study and play the piano, composed some of the most well-known songs of all time. Which p
hrase 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.
The body gives reasons because it is where you give evidence and reasoning. The introduction just introduces a topic while a the thesis does the same. The conclusion ends the writing so the only logical answer is the body.