In Lean thinking the customer defines $\text{'}\text{'}$value$\text{'}\text{'}$ or $\text{'}\text{'}$value$-$added'$\text{'}$ based on which of the following conditions?

a$.$ It must transform the product or service

b$.$ The customer must be willing to $\text{'}\text{'}$pay$\text{'}\text{'}$ for $\text{'}\text{'}$it$\text{'}\text{'}$

c$.$ It must be done correctly the first time

d$.$ All of these are correct