Position and style of back button in web - User Experience Stack

After studying about the 'Back' button, I still can't decide on which best suited my case. I am designing an internal portal where the content varies in width. Button position: A.1 Right side seems

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website design - Should a web-based UI rely on the browser back button? - User Experience Stack Exchange

website design - Should a web-based UI rely on the browser back button? - User Experience Stack Exchange

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