shyind wrote:

Using a computer model to estimate future productivity, the accuracy of such an estimate is higher than that achieved using more subjective methods.

The non-underlined portion talks about "

the accuracy of such an estimate", hence in the previous clause, "the estimate" needs to be introduced.

A. Using a computer model to estimate future productivity----

this is illogically modifying "the accuracy" B. By the use of a computer model to estimate future productivity-----

Modifier problem C. If a computer model is used to estimate future productivity----

Correct. this clause introduces "a computer model" that has been described in the next clause D. With a computer model for estimating future productivity-----

Incorrect modifier, modifying the accuracy E. Estimating future productivity with a computer model-----

Same issue as D