Answer:
B should be selected.
Explanation:
Below is the calculation of net present worth:
Present value of A = -500000 - 25000 * (P/A, 7%,18)
Present value = -500000 - 25000 * 10.059087
Present value = -751477.17
Present value of B = -640000 - 10000 * (P/A, 7%,18)
Present value = -640000 - 10000 * 10.059087
Present value = -740590.87
The present value of B is lower so it will be selected.