Answer:
Punctuation
Explanation:
The sentence started with the double quotes and it should be closed appropriately. All the single quotes and double quotes are paired punctuation and mostly they do not come alone.
Note that there is a difference between a single quote and apostrophe though same key is used from the keyboard for both. The correct answer is Punctuation.
George W. Bush is the President of the United States of America”. There is one another error in the statement. At present Bush is not the President so the sentence can be George W. Bush was the President of the United States of America.