Shoppers in sporting goods stores, unlike in department stores, do very little impulse shopping, not buying a pair of skis and a boomerang when they come in for a basketball, but they leave with a basketball only.
C. do very little…, do not buy…, but leave… 三个动词变成并列关系。而原文,not buy a pair of skis and a boomerang 和 leave with a basketball都是解释 do little impulse shopping,并不是并列。C犯了改变句子强调中心的错误,一定错. 另外,not buy … 和 leave 不是转折关系,不用but.