请阅读下面短文，根据短文内容从每小题所给的A，B，C，D,选出最佳选项。
"What?
You too? I thought I was the only one." Have you ever said to someone? If
so, you may have ended up becoming friends.
It seems
that similarity often helps form a friendship. Aristotle once said, "Some
define (给……下定义) it
(friendship) as a matter of similarity; they say that we love those who are
like ourselves."
Now, there
are some scientific explanations for this idea. The scientists from the
University of California said friends have similar brains, Scientific American
reported.
The
scientists invited 42 university students to take part in a scientific test. Each
student watched the same set of videos. At the same time, the scientists
scanned (扫描) their
brains and recorded their brain activities.
According
to their study, friends who watched the same videos reacted (反应) in similar ways. Similar parts
of their brains lit up while watching the videos, especially the parts that
were connected with motivation, learning and memory. However, people who weren't
friends had different reactions to the same videos.
"Having
close friends whose brains react like ours may be rewarding because it
reinforces (加强) one's own
values, opinions and interests," lead scientist Carolyn Parkinson told
Business Insider.
But brain
similarity is not the only thing that can result in a friendship. Scientists
from the University of Leipzig, Germany, found that a friendship is also based
on how physically close you are to someone. They did a scientific test on
first-year college students who met in class for the first time. In this test,
students who sat next to each other were more likely to become friends.
