In one hour, Sally can complete 4 reports or she can write 8 computer programs. Calculate the opportunity cost for this scenario. 从以下选出正确答案,并用英文解释为什么选它。 A). Writing one report and forgoing 2 computer programs B). Writing one report and forgoing 3 computer programs C). Writing one report and forgoing 4 computer programs D). Writing one report and forgoing 5 computer program