Final answer:
C.P.E. stands for Carl Philipp Emanuel Bach, an influential 18th-century German composer and son of Johann Sebastian Bach.
Step-by-step explanation:
The initials C.P.E. stand for Carl Philipp Emanuel Bach, who was a German composer, keyboardist, and one of the most important composers of the 18th century. He is a prominent figure in music history, especially for his contributions to the development of the Classical style in music during the second half of the 18th century. C.P.E. Bach was the second surviving son of Johann Sebastian Bach and Maria Barbara Bach, and his music is an example of the transition from the Baroque to the Classical era.