Questions 16～20

Napoleon famously described the British as a nation of shopkeepers. These clays it would be equally true to describe them as a nation of shoppers. Either way, London is the UK’s shopping mecca; if you can’t find it here you probably can’t find it at all.
Some London shops are more or less tourist attractions in their own right. Few visitors come away without popping into Harrods. This famous store is a real one-off. The toilets are lab, the food hall enough to make you swoon, and if they haven’t got what you want, it probably doesn’t exist. No other store has such a sense of sheer, outrageous abundance. Since Absolutely Fabulous brought Edina and Patsy steaming onto our screens, Harvey Nichols ("Harvey Nicks") has become another must-see attraction. It boasts a great food hall, an extravagant perfume department and jewellery to save up for. But with all the big names from Miyake to Lauren, Hammett to Calvin Klein and a whole floor of up-to-the-minute menswear, it’s fashion that Harvey Nichols does better than the rest. The selection is unrivalled and the prices high, although the sales offer some great bargains, and the store’s own clothing line is reasonable.
Carnahy Street still reeks of the 60s although it’s had something of a revival since the "Cool Britannia" kick brought Union Jack dresses back into fashion. The last punks have long since slunk away from Chelsea’s King’s Rd but there are still plenty of interesting shops slotted in amid the high-street chains.
Oxford St and classier Regent St come into their own in the six weeks running up to Christmas when they’re festooned with lights. At other times of the year Oxford St can be a great disappointment. Selfridge’s is up there with Harrods as a place to visit and the farther east you go the tackier and less interesting it becomes.
Although most things can be bought in most parts of town, there are also streets with their own specialties; Tottenham Court Rd, for example, is one long electrical goods shop (watch out for rip-offs though), while Charing Cross Rd is still the place to come for offbeat books.
Many tourist attractions have excellent shops selling good-quality souvenirs like mugs, pens, pencils, stationery and T-shirts, often with themes to match their content (war books and videos at the Imperial War Museum). By buying from these shops you help contribute towards the building’s maintenance, especially important in the cases of those without entry charges.

According to the writer, when is the best shopping time at Oxford St

A. All the year round.
B. November and December.
C. Only Christmas week
D. It is not mentioned.