Final answer:
The item not relevant in cash flow estimation is the regular meeting fees for the board of directors, as these are considered sunk costs. Instead, changes in inventories and accounts receivable related to the project are relevant for calculating incremental cash flow.
Step-by-step explanation:
The item that is not relevant to consider in cash flow estimation is c. regular meeting fees for the board of directors incurred when the go-no go decision is made. This is because these are considered sunk costs, which are costs that have already been incurred and cannot be recovered. Sunk costs should not influence the cash flow estimations for new projects, as cash flow analysis should focus on incremental cash flows - the additional cash flow a new project brings into the company.
Items such as a change in inventories and a change in accounts receivable due to the project (options a and b), are relevant in cash flow estimation. When a company considers reinvesting profits, it examines the changes in working capital, like inventory and accounts receivable, to estimate the additional cash flow generated from such reinvestment that can lead to growth. Consequently, careful analysis of these factors, excluding sunk costs, is essential for accurate cash flow projections and business decisions.