Before electronic amplification, theater crews relied on ingenious mechanical devices to create convincing sounds. A museum exhibit presents three examples: a thunder run, a wooden channel down which iron balls were _____ and a rain box, a rotating container in which dried peas struck a metal lining.
Which choice completes the text so that it conforms to the conventions of Standard English?
For a complex series, reduce each item to its central noun or phrase before evaluating the punctuation. If the items contain internal commas, check that semicolons consistently mark every top-level boundary in the series.
Hints
Reduce the series
Temporarily ignore the descriptive phrase following each device name. Identify the three top-level items in the list.
Track both boundaries
Distinguish the commas used inside the descriptions from the punctuation needed between the top-level items. Check both boundaries supplied by each option.
Step-by-step Explanation
Identify the main series
The sentence names three top-level examples: a thunder run, a wind machine, and a rain box.
Separate descriptions from list items
Each device name is followed by a descriptive phrase containing a comma. Those commas function within the individual list items rather than between the three devices.
Mark both top-level boundaries
Because the list items contain internal commas, semicolons clearly separate the first item from the second and the second item from the third. The correct completion places a semicolon after both “rolled” and “sound.”