please answers this question and be specific

Assume that your company decides to build a plant. It will take four year to build this plant and the compnay will spend 1m dollars during each of the next four years.

Let us assume that at the end of year three the economics of the market change and the company must now decide whether to continue building he plant, or close it down.

Are the investments in years 1 to 3 relevant to this decision?