单选题 Smog-choked Southern California A demands them. It's a car for people who never want to go to B a gas station again. But the fact is, for all the talk, selling C gas-less machines has been a D hard-sell .
【正确答案】 A
【答案解析】解析：A应改为is demanding。A项的动词应用现在进行时的形式。