Read the following passage and questions, then choose the right answer from options, the answer should be one of A, B, C, D.

<passage>:
My Father's Estate A letter from an ill-mannered former high-school classmate of long ago, one of several like it, which I pass on in paraphrase: "I saw that your father had died," she wrote. "He was always so clever about money. Did he leave you a big estate? Did he figure out a way around the estate tax?" It's a rude question, but it has an answer. My sister and I have been going through my father's estate lately with his lawyer, and we're pawing through old, dusty files to find bank account numbers and rules for annuities, so maybe it's a good time to think about what my father, Herbert Stein, left to us. He did indeed leave some money. By the standards we read about in the Wall Street Journal or Sports Illustrated , it was not worthy of much ink. In any event, because of the class-warfare-based death tax, the amount that will be left is vastly less than what he had saved. As an economist, my father was famous for defending taxes as a necessary evil. But even he was staggered, not long before his death, when he considered the taxes on his savings that would go to the Internal Revenue Service. The nest egg is going to be taxed at a federal rate of about 55 percent, after an initial exemption and then a transition amount taxed at around 40 percent (and all that after paying estate expenses). When I think about it, I want to cry. My father and mother lived frugally all their lives. They never had a luxury car. They never flew first-class unless it was on the expense account. They never in their whole lives went on an expensive vacation. When he last went into the hospital, my father was still wearing an old pair of gray wool slacks with a sewed-up hole in them from where my dog ripped them--15 years ago. They never had live-in help. My father washed the dishes after my mother made the meatloaf. My father took the bus whenever he could. His only large expenditure in his and my mom's whole lives was to pay for schools for his children and grandchildren. He never bought bottled, imported water There are a few material, tangible items that an assessor will have to come in to appraise. There are my father's books, from his days at Williams College and the University of Chicago, many of them still neatly underlined and annotated in his handwriting, which did not change from 1931 until days before his death. Most of them are about economics, but some are poetry. Some of them will go to the Nixon Library, and some will be on bookshelves in the (very small and modest) house my wife and I own in Malibu, a place he found beguiling because he had always wanted to live by the ocean and write. And there are his furniture and his clothes, none of which has any value at all except to me because they remind me of him and because, when I stand near them in his closet, I can still smell his smell of hair and skin and leather shoes, the closet smelling a lot like he smelled when he came home from work in 1954 carrying a newspaper that said there could be no more racial segregation in schools. And there are his mementos of Richard Nixon, his White House cufflinks, photos of Camp David, certificates and honorary degrees, and clippings of great events of state. And there are his love letters to and from my mother when they were courting in 1935 and 1936, still tied with light blue ribbon in what was my mother's lingerie drawer, talking about their love triumphing over the dangers of the Depression. I suppose we'll have to place a value on these and have them taxed, too. But these are the trivia of what he left me and my sister. The really valuable estate cannot be touched by the death tax. The man's legacy to his family has almost nothing to do with anything that can be appraised in dollars and cents. "Loyalty." There is no item for it in the inventory of estate assets to be taxed. My father lived his life, especially in the latter years of it, in a haze of appreciation. Whatever small faults he could and did find with America, he endlessly reminded anyone who listened that the best achievement of mankind was America, whose current failings were trivial by historic standards, which was in a constant process of amelioration, and which offered its citizens the best chance in history for a good life. When he did consider the failures of American life in the past, especially institutionalized racism, he did so to note the astonishing progress that had been made in his lifetime. He had no use for those who held up a mirror of fault-finding from the left or the right when he could see in his own era what vast improvements in freedom had been made for blacks, Jews, women, Asians, Hispanics, and every other minority. This quality of gratitude for America and for the beauty of life cannot be taxed, at least not so far. He appreciated his friends and did not differentiate between them on the basis of fame or position. He took the words of his longtime pal Murray Foss at the American Enterprise Institute, a think tank where he hung his hat for many years, into account My father's stance against seeking money for its own sake--so wildly unsuited to today's age, but so reassuring to his children--cannot be taken by the Treasury. My father himself, as far as I know, inherited no money at all from his father. He did inherit a belief that hard work would solve most problems, that spending beyond one's means was a recipe for disaster, that flashy showoff behavior with borrowed money was understandable but foolish. He did inherit enough common sense to tell his son that buying property he would never live in was probably a bad mistake. (He rarely spoke in moral absolutes. He believed instead that humans could and would make individual choices but that there were surely consequences to those choices that could be considered.) He passed these beliefs on to me, although they have become somewhat attenuated by my 20-plus years in the fleshpots of Hollywood. Still, I am one of the only men I know here who has never been drastically short of money (so far), and that I attribute to hearing his rules of prudence. Even in his hospital bed, hearing my son's voice on the phone could make him smile through the fear and the pain. ("He sounds so sweet when he calls me 'Grandpa,' " my father said, beaming even with tubes in him.) Never once did my sister or I ever ask him for help that he hesitated, let alone declined, to give. Usually this was some research we were too lazy to do, but which he did without any resistance at all. When I was a child and had a chore like leaf raking that I didn't want to do, his simple answer was to say, "Let's do it together. It'll take half as long." I use that with my son almost every day, along with the devotion, and my father's example about his friends from long ago to make my life work. He stayed close with friends from Williams College Class of '35, especially Richard Helms of the CIA. He had lunch with one of his pals from Williams, Johnny Davis, class of '33, who got him a job as a dishwasher at Sigma Chi, days before he went into the hospital. This quality of devotion and the rewards I get from it are worth far more than any stocks or bonds in my father's estate--and cannot be taken away at the marginal rate of 55 percent. Plus, I can pass it on to my son without any generation-skipping surcharge.

<question>:
Why does the author discuss his father's clothing and mementos?

<options>:
A They are things he wants to sell
B They will have to be valued and taxed
C They are the biggest part of the estate
D They are nostalgic to him

<answer>:

D