An input to the process to optimize the portfolio is:

Portfolio process assets encompass existing policies, procedures, templates, and lessons learned that guide how portfolio optimization is conducted. They are a standard input in the PMI portfolio management framework, providing the organizational knowledge base from which the optimization process draws.

The portfolio charter is an input to the defining and aligning process groups, not specifically to the optimization process.

Capability and capacity analysis is a tool and technique used within portfolio management processes, not an input to portfolio optimization.

Quantitative and qualitative analysis are tools and techniques applied during portfolio optimization, not inputs to it.