The correct answer is E. prolix.

The key to solving this sentence is the phrase "took eight hours to perform and was executed over two consecutive nights," which describes the play's excessive length.
- E. prolix: This means using or containing too many words; excessively long. This word perfectly fits the description of a play that is so long it takes two nights to perform.

Let's look at the other options and why they don't fit:
- A. pedantic: This refers to someone who is excessively concerned with minor details and rules or with displaying academic learning. This doesn't relate to the play's length.
- B. odious: This means extremely unpleasant or repulsive. While the play might have been unpleasant to watch, the primary characteristic described is its length, not its quality.
- C. onerous: This means involving a great deal of effort, trouble, or difficulty. The play was likely difficult to sit through, but "prolix" more directly describes the reason for the difficulty.
- D. moribund: This means at the point of death; in terminal decline. While the play closed quickly, "moribund" describes its state, not its inherent nature or length, which is the focus of the sentence.