300. Following the destruction of the space shuttle Challenger, investigators concluded that many key people employed by the National Aeronautics and Space Administration and its contractors work an excessive amount of overtime that has the potential of causing errors in judgment.
(A) overtime that has the potential of causing ackward wording
(B) overtime that has the potential to cause ackward wording
(C) overtime that potentially can cause ('can' should be placed before 'potentially')
(D) overtime, a practice that has the potential for causing
(E) overtime, a practice that can, potentially, cause

Please EXPLAIN your answer.

(A) overtime that has the potential of causing
(B) overtime that has the potential to cause
(C) overtime that potentially can cause
(D) overtime, a practice that has the potential for causing
(E) overtime, a practice that can, potentially, cause

Please EXPLAIN your answer.

300. Following the destruction of the space shuttle Challenger, investigators concluded that many key people employed by the National Aeronautics and Space Administration and its contractors work an excessive amount of overtime that has the potential of causing errors in judgment.
(A) overtime that has the potential of causing
(B) overtime that has the potential to cause
(C) overtime that potentially can cause
(D) overtime, a practice that has the potential for causing
(E) overtime, a practice that can, potentially, cause

Please EXPLAIN your answer.

I would go with "B"

what's the OA?

I agree OT is not a practice

300. Following the destruction of the space shuttle Challenger, investigators concluded that many key people employed by the National Aeronautics and Space Administration and its contractors work an excessive amount of overtime that has the potential of causing errors in judgment.
(A) overtime that has the potential of causing -->unidiomatic
(B) overtime that has the potential to cause
(C) overtime that potentially can cause-------> "can" is redundant
(D) overtime, a practice that has the potential for causing----> unidiomatic
(E) overtime, a practice that can, potentially, cause------> "potentially" is an adverb that modifies verb "cause" not "can" as it is in C.

Please EXPLAIN your answer.

300. Following the destruction of the space shuttle Challenger, investigators concluded that many key people employed by the National Aeronautics and Space Administration and its contractors work an excessive amount of overtime that has the potential of causing errors in judgment.
(A) overtime that has the potential of causing
(B) overtime that has the potential to cause
(C) overtime that potentially can cause
(D) overtime, a practice that has the potential for causing
(E) overtime, a practice that can, potentially, cause

Please EXPLAIN your answer.

A, B, and C have modifier issues. "That" introduces an essential noun modifier, but the information following the word "that" is not essential in order to understand the meaning of the words coming before the word "that" - rather, the stuff after the word "that" makes an additional, but separate, point. Also, "that' introduces a noun modifier, but the noun before is not what they're trying to refer to - they're trying to refer to the fact that they work an excessive amount of overtime. That's a whole clause, not just a noun.

To know whether something is essential, try stopping the sentence at the word "overtime." Do you still understand everything that was written to that point? Sure. You've lost the meaning of the extra words, but it hasn't messed up the meaning of the words up to the word "overtime." Then look at choices D and E - they introduce "that" after the words "a practice." Can you stop at "a practice" now and still know what they're talking about? Nope.

Now, between D and E, you do have to know that they consider "has the potential for causing" wordier than "can, potentially, cause. Fewer words, yes, but also just using the verb form (since we're talking about an action, that's preferred to writing the verb in noun form).

"potential to" --> just describes a potential effect of something; may or may not be intentional or aimed at some goal
"potential for" --> used only when a specific goal is intended. in the first sentence, this goal is the relieving of severe pain.

causing errors in judgment is definitely not a goal or intended effect, so "potential for" is incorrect in that sentence.