The symbol on the top of the backrest of the President's chair was the American flag. The Option B.
The American flag on the President's chair serves as an iconic symbol that represents the United States and its values, with its stars and stripes embodying the nation's history and unity.
The choice of the American flag for such a prominent position in the President's chair underscores the importance of patriotism and national identity in the country's highest office.
In conclusion, this serves as a powerful reminder of the principles and ideals upon which the United States was founded.