大全372——并列问题

372.        In contrast to large steel plants that take iron ore through all the steps needed to produce several different kinds of steel, processing steel scrap into a specialized group of products has enabled small mills to put capital into new technology and remain economically viable.

(A) processing steel scrap into a specialized group of products has enabled small mills to put capital into new technology and remain

(B) processing steel scrap into a specialized group of products has enabled small mills to put capital into new technology, remaining

(C) the processing of steel scrap into a specialized group of products has enabled small mills to put capital into new technology, remaining

(D) small mills, by processing steel scrap into a specialized group of products, have been able to put capital into new technology and remain（D）

(E) small mills, by processing steel scrap into a specialized group of products, have been able to put capital into new technology and remained

我想问各位的是关于这道题的and的并列问题：

D选项的remain是和put capital的put并列吗？

能不能把remain看做是和have been able的have并列？即“现在完成时和一般现在时的并列”，行不行？

为什么E不对？即把remained看做和been able to的been并列。即看做：have been able to...and (have) remained...

我觉得这在意思上说得过去啊！

请指教！