Choice A is the correct answer. Variables on both sides require systematic isolation.

1. Subtract 3x: $7x - 3x - 4 \geq 3x - 3x + 12$, giving $4x - 4 \geq 12$
2. Add 4: $4x - 4 + 4 \geq 12 + 4$, giving $4x \geq 16$
3. Divide by 4: $x \geq 4$

?�� Strategic Tip: Move all variable terms to one side before working with constants to avoid confusion.

Choice B is incorrect because it reverses the inequality without mathematical reason. Choice C is incorrect because it might result from incorrect arithmetic, perhaps dividing 8 by 4 instead of 16. Choice D is incorrect because it combines both wrong value and wrong direction.