Answer:
D). Too many plans in life prevent people from being happy and fulfilled.
Step-by-step explanation:
The key idea which the author conveys through the given story is that 'having too many plans in life abstains people from being happy and fulfilled.' The author says that the excess pressure that we put on ourselves by making such grand plans not only creates unwanted obstacles and problems which we never expect but also ruins individual happiness. This idea is supported through the description of 'rejections and obstacles' that the speaker faced in his huge 10-year plan' which led him to suffer a 'gross understate.' This suggests that we make huge plans without considering the uncertainties and challenges that will come our way and it eventually mars one from their happiness. Thus, option D is the correct answer.