Answer: Choice B
A horizontal shift of 4 to the right.
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Reason:
Replacing x with x-4 basically means we're decreasing each input by 4 units.
What this does is move the xy axis 4 units to the left. If we held the function curve fixed in place as the xy axis moved like this, then it would give the illusion the function is moving 4 units to the right.
Visual confirmation is shown below.