Which of the choices is correct?

Why must real options have positive value?

Problem 9-20 Question Help ' Q Why must real options have positive value? (Select all the choices that apply.) 3 A. If exercising the real option would reduce value, managers can allow the option to go unexercised. 3 B. Having the real option but not the obligation to act is valuable :I C. Real options must have positive value because they can always be sold to recover the initial investment. :| D. Real options must have positive value because they are only exercised when doing so would increase the value of the investment