The concept of all contributors to a project giving painfully honest and $50\%$ confidence$-$level estimates instead of adding padding, and collecting the $$padding$$ for use by the entire project, to protect the end date is part of a philosophy developed by Eliyahu Goldratt called:

a$.$

DevOps

b$.$

Shift Left

c$.$

Critical Chain

d$.$

Measure Once, Cut Twice