Answer:
A. Transformation to rock and roll
Step-by-step explanation:
Rock and Roll is a style or genre of music that infused various forms of musical style together.
It started around the 1940s during which the use of an emphasized backbeat in the rhythm-and-blues, mixed with elements of the genres of other music like gospel, jazz, boogie-woogie, and country music to transform to rock and roll.
Hence, in this case, the correct answer is option A "A. Transformation to rock and roll."