You are a new project manager seeking to better understand agile project management. Which one of the following is NOT a principal of the Agile Manifesto:

a$.$ Agile is an approach that emphasizes a linear progression from beginning to end of a project.

b$.$ Agile process is meant to create sustainable development, which demands sponsors, developers, and users work at the same pace for a long period.

c$.$ Uninterrupted attention to technical excellence and good design boosts agility.

d$.$ Simplicity$-$the art of maximizing the amount of work not done$-$is essential.