Answer:
B
Step-by-step explanation:
The definition of súbito is suddenly. A súbito p would mean the dynamic suddenly changed to piano. A quick jump from very loud to soft is a similar use of súbito p as it becomes suddenly piano(soft). B is an incorrect usage because it says it’s a “gradual change” in the dynamic from mezzo forte to forte, which isn’t even that big of a dynamic change in general. This is not sudden as it states the antonym of súbito, being gradual. So, B is the answer.