The truth about left-handed peop

The truth about left-handed people
About 90% of people in the world today are right-handed. The other 10% are left-handed, including Obama, the president of the US. Every day, left-handed folks quietly face problems. It could be something as simple as driving a car or using a can opener.
Why are so few of us left-handed? One theory is that handedness (hand preference) could be a result of genetics. Scientists say that there are two genes(基因) associated with handedness. One is the D gene. It is more frequent in the population and promotes（促成）right-handed preference. The other is the C gene. It has the ability to promote a preference for either hand. When the C gene is present, there is a 50% chance that a person could be right-or left-handed.
Another theory has to do with human brains, which are made up of two halves. If the left hand is more powerful, then one is most likely right-handed. But with left handers, it is more complicated. Seventy percent of them are also left-brain dominant（占优势的）. The other 30% have right-side dominant brains.
During the 18^thand 19^th centuries, left-handedness was considered a disability. But not all of the myths about left-handers are bad. One myth suggests that they are more creative and smarter than the right-handers. So far scientific research has yet to find any truth to these claims. In fact, a 2013 survey out of New Zealand found that left-handers and right-handers were the same.
Life might be a little more complicated for left-handers when it comes to cutting a piece of paper or opening a bottle of wine. However, it seems to be a good sign if you are trying to make it to the white house.

Left-handers are proved to be clever.
A、True
B、False
C、Not given
【正确答案】：B
【题目解析】：解析：原文第三段最后确实说到有人认为左撇子更聪明，但2013年新泽西的调查研究表明两种人没有区别，所以答案是B