Choice Choice A is the correct answer.

1. Start with the equation: $6x - 12 = 36$
2. Add 12 to both sides: $6x = 36 + 12$
3. Simplify: $6x = 48$
4. Divide both sides by 6: $x = \frac{48}{6}$
5. Simplify: $x = 8$
6. Verify: $6(8) - 12 = 48 - 12 = 36$ ✓

Choice Choice B is incorrect because this results from subtracting 12 from 36: $24$, then $24/6 = 4$. We must add to undo subtraction.

Choice Choice C is incorrect because this is the value of $6x$. You must divide by 6.

Choice Choice A is incorrect because this results from multiplying 48 by 6: $288$.