Read these sentences from the passage. Scientists have noticed that birds near cities have changed their song. The pitch has gone up, which makes it easier for
them to hear each other when they are close together.
What is the best way to paraphrase these sentences?
A. According to scientists, birds have changed their song near cities; it is easier for birds to hear each other
when they are close together, since the song pitch has gone up.
B. Scientists observed that near cities, birds in close proximity use higher-pitched songs to better hear one
another.
C. According to scientists, birds near cities have changed their song to have a higher pitch, which makes it
easier for them to hear each other when they are close together.
D. Scientists have noticed that since the pitch has gone up in birdsong near cities, it is easier for them to hear
each other when they are close together.