The possibility for a company to postpone, modify or abandon capital investments, refers to: a

The possibility for a company to postpone, modify or abondon capital investments refers to Real option.

Real option includes decision which involves expanding, deferment or complete abondoning of a project.

Thus Option B is the correct answer.

Option A which states incremental cash flows is wrong as it means the increase in the cash flows. It refers to the increase in the amount of cash flows which is no way related to the above statement.

Option C which states opportunity cost is wrong as it means the cost of chosing one option over the above, other being the opportunity cost for the first option. For example, there are 2 options of investment at 5% and 6%, chosing the option with 6% will lead to 5% being its opportunity cost.

Option D is wrong as it states a positive NPV of the project, which is no where related to the above statement again. A positive NPV means the profitability of a project with respect to the discounted cash inflows and outflows.

Hence option B, Real option is the correct answer.