Question

_____ are often the most poisonous.
which choice completes the text so that it conforms to the conventions of
standard english?
choose 1 answer:
a frogs—with the most brilliant colors and patterns—
b frogs, with the most brilliant colors and patterns—
c frogs (with the most brilliant colors and patterns)
d frogs with the most brilliant colors and patterns

Explanation:

This question tests correct parenthetical punctuation for non-restrictive clauses. Option A uses em dashes correctly to set off the non-essential descriptive phrase without grammatical errors. Option B incorrectly mismatches a comma with an em dash. Option C uses parentheses but the sentence structure would leave an awkward gap before the main verb "are". Option D does not set off the descriptive phrase, making the sentence read as if only these specific frogs are the subject without proper separation of the clarifying detail.

Answer:

A. Frogs—with the most brilliant colors and patterns—