Answer:
Held Up
Explanation: If we take each option and place it in the blank of the sentence, we can see which one makes the most sense.
A. The train was <em>held back</em> by a heavy snowfall.
B. The train was <em>held out </em>by a heavy snowfall.
C. The train was <em>held off </em>by a heavy snowfall.
D. The train was <u>held up</u> by a heavy snowfall.
D. That all aspects of the piece should work together to create a certain effect
To create a "unity of effect" on the reader, it should have a certain effect on the reader. Like a really sad and depressing book should not exactly make the reader sad, but to feel the parts of the book that spoke out to the reader.
