<span>A) The comma attempts to set apart an essential element.
One comma rule is that you cannot use commas to set off essential parts of the sentence. The usage of two commas can only go around nonessential clause, meaning a clause that can be removed and the sentence will still make sense. However,</span><span> clauses beginning with a "</span>that"<span> that follows a noun are always essential! </span>
C) the systematic use of symbolism to convey a theme
Answer:
C. While foreign migrant workers are forced to leave the United States after a period of time, migrant workers from within the United States are able to stay and work indefinitely.
Explanation:
The author was trying to let us know that, due to the type of visa which the migrant workers have, they have no choice than to leave the US after the expiring of the validity while on the otherhand, the migrant workers from within US never had such issue.
