请教nn一道语法题...谢谢:)

The growth of the railroads led to the abolition of local thimes ,which was determined by when the sun reached the observer's meridian and differing from city to city , and to the establishment of regional times.

A which was derermined by when the sun reached the observer's meridian and differing

B which was determined by when the sun reached the observer's meridian and which differed

C which were determined by when the sun reached the observer's meridian and differing

D determined by when the sun reached the observer's meridian and differed

E determined by when the sun reached the observer's meridian and differing

   能解释下这道题目吗?答案E