Option B is wrong, please explain.

Concept Check Question 27-10 x] This is one of the assumptions made when applying the net present value method but (d) is a better response. Which of the following is not one of the simplifying assumptions made when applying the net present value method? All cash flows come at the end of each year. All cash flows are immediately reinvested in another project that has a similar return. All cash flows can be predicted with certainty. All of the above are assumptions made when applying the net present value method