Many of today's mathematicians use computers to test cases that are either too time-consuming or involve too many variables to test manually, allowing the exploration of theoretical issues that were impossible to test a generation ago.

A. are either too time-consuming or involve too many variables to test manually, allowing the exploration of
B. either take too much time or involve too many variables to be tested manually; allowing the mathematicians to explore
C. would either take too much time or involve too many variables to test manually, allowing them to explore
D. would either be too time-consuming or would involve too many variables to test manually; this capability allows the mathematicians to explore
E. take too much time or variables to test manually; this capability allows the mathematicians to explore

My question: in E, is the clause after the ";" correctly used? This capability => refers to => using computers to test such cases ???