B. Though Benjamin Franklin was known for his instrumental role in the founding of the United States.
This is a sentence fragment, you can tell because saying the sentence in your head or out loud feels incomplete, that is because the sentence wasn't finished, for example, "Though Benjamin Franklin was known for his instrumental role in the founding of the United States, he had many other accomplishments." Is a full sentence.
A seven letter word containing thousands of letters - a mailbox.
The word mailbox has 7 letters, and it contains thousands of letters - just not the letters from the alphabet, but rather a form of a paper message.
