求解prep172题里边同位语的问题

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Introduced by Italian merchants resident in London during the sixteenth century,in England life insurance remained until the end of the 17th century a specialized contract between individual underwriters and their clients,typically being ship owners,overseas merchants,or professional moneylenders.
A.in England life insurance remained until the end of the 17th century a specialized contract between individual underwriters and their clients,typically being
B.in England life insurance had remained until the end of the 17th century a specialized contract between individual underwriters with their clients,who typically were
C.until the end of the 17th century life insurance in England had remained a specialized contract between individual underwriters and their clients,typically
D.life insurance in England remained until the end of the 17th century a specialized contract between individual underwriters and their clients,typically
E.life insurance in England remained until the end of the 17th century in England a specialized contract between individual underwriters with their clients,who typically were这道题答案选D，解释里说a contract 做life insurance的同位语，但是，同位语与其所修饰的名词之间不应该有逗号吗？也就是说，17th  century 和 a specialized contract中间是不是应该有一个逗号？
这句话怎么翻译呢？