How does SAFe recommend using a second operating system to deliver value?

How does SAFe recommend using a second operating system to deliver value?
A . Organize development around the flow of value while maintaining the hierarchies
B . Build a small entrepreneurial network focused on the Customer in place of the existing hierarchies
C . Decide whether to apply a hierarchical or Value Stream organizational model across the Enterprise
D . Reorganize the hierarchies around the flow of value

Answer: A