问一道SAT写作题

问一道SAT写作题
which is the best way to combine these two sentences below?
In royal palaces there were to be found many comforts that medieval castles did not offer.These had dark dungeons and many more comforts than could be found threr.
有三个选项我都觉得可以.
1) While medieval castles offered only dark dungeons and damp,drafty living quarters,many comforts were to be found in royal palaces.
2) Unlike medieval castles,royal palaces offered many comforts not found in dark dungeons and damp,drafty living quarters.
3) With their dar dungeons and damp,drafty living quarters,medieval castles offered few of the comforts to be found in royal palaces.
我选了第一个,但是正确答案是第三个.
求分析!