What are the most important topics to cover during music studies for high school?

The correct option is D

Movies had no music until the 1930's.
The silent film had neither dialogue nor sound. This was due to the type of gadgets that were used to capture images then. the transition from silent film begun in the 1927s. However, a number of motion pictures film, atypical to the past era were still being produced though in smaller quantities. The synchronization was only possible after the discovery of the vita phone and the Audion amplifier tube.