Read the following sentence, and then choose the option with correct comma placement.
His books in my opinion are so similar that it's difficult to distinguish one plot from the other.
Group of answer choices
His books in my opinion are so similar that it's difficult to distinguish one plot from the other.
His books, in my opinion are so similar that it's difficult to distinguish one plot from the other.
His books, in my opinion, are so similar that it's difficult to distinguish one plot from the other.
His books in my opinion, are so similar that it's difficult to distinguish one plot from the other.