77. Using the techniques employed by genetic engineering, a new species of microorganism has been developed by laboratory scientists to aid in cleaning up oil spills by digesting the oil.
(A) Using the techniques employed by genetic engineering, a new species of microorganism has been developed by laboratory scientists to
(B) Using the techniques employed by genetic engineering, a new species of microorganism that was developed by laboratory scientists will
(C) Using the techniques of genetic engineering laboratory scientists have developed a new species of microorganism to
(D) Employing the techniques of genetic engineering there has been a development by laboratory scientists of a new species of microorganism that will（C）
(E) Employing the techniques of genetic engineering, a new species of microorganism that was developed by laboratory scientists will
C中的using the techniques of genetic engineering,这里不应该是有个逗号的么?
E为什么错? | 
