What is "Lean Manufacturing," and what is a common tool used in its implementation?

a$)$ Lean Manufacturing aims to maximize product variety. A common tool used is product diversification analysis.

b$)$ Lean Manufacturing focuses on eliminating waste and improving process efficiency. A common tool used is Value Stream Mapping $($VSM$)$ to identify and remove non$-$value$-$added activities.

c$)$ Lean Manufacturing targets increasing production capacity. A common tool used is capacity planning software.

d$)$ Lean Manufacturing involves standardizing employee roles. A common tool used is job rotation schedules.