Final answer:
The incorrect punctuation mark is the apostrophe in 'parents'' (option D). It's used incorrectly because 'parents' in this context is meant as a plural noun and should not have an apostrophe.
Step-by-step explanation:
The question asks about the correct use of punctuation, specifically the use of apostrophes and commas in the context provided. The use of the apostrophe in 'Parents' Day' is correct, as it signifies a day belonging to parents, indicating possession.
The commas following 'Day' and 'Congo' are also correctly used as they serve to separate clauses and geographical names respectively. The incorrect use of punctuation is found in option D, the apostrophe in 'parents'.
As per the context given, 'parents' should not have an apostrophe because it is meant to be a plural noun, not a possessive noun. Apostrophes should not be used to form plural nouns, and in the sentence provided, 'parents' is intended as a plural noun referring to more than one parent.
If 'parents' was intended as possessive, it would need to be followed by another noun that they own or are closely tied to, such as in the sentence 'During the pandemic, parents' stress grew as they helped with their children's schooling.'