What is the key difference between resource smoothing and resource leveling?

Group of answer choices

A$)$ Resource smoothing allows the project timeline to extend, while resource leveling does not

B$)$ Resource leveling focuses on adjusting total resource allocation, while resource smoothing reduces variation in resource usage

C$)$ Resource smoothing is used when the project has a strict deadline, while resource leveling is for projects with a flexible end date

D$)$ Resource leveling aims to speed up the project completion, while resource smoothing seeks to create a more sustainable pace