Can u ? ? brainliest will be given to best answer (plz use attachments) i think its isaac singer but i'm confused between a. & c.

Which statement is true with regard to beethoven? a. ludwig vin kochel catalogued more than six hundred of his compositions. b. he was the official composer for the powerful and rich eszterhazy family. c. he produced the best piano sonatas and the “ninth symphony” after losing his hearing. d. he wrote the well-known opera “the magic flute” during the last years of his life.

Organum was first developed by religious singers adding another melody directly above the chant and mirroring the chant line. true false

Poussin was responsible for establishing what as a key component of 17th century french art