Choice Choice B is the correct answer. We add to undo the subtraction.

1. Start with the equation: $x - 6 = 19$
2. Add 6 to both sides: $x = 19 + 6$
3. Calculate: $x = 25$
4. Verify: $25 - 6 = 19$ ✓

The pattern is consistent: subtraction is undone by addition.

Choice Choice C is incorrect because this results from subtracting 6 from 19 instead of adding: $19 - 6 = 13$. This applies subtraction twice.

Choice Choice D is incorrect because this is the negative of Choice Choice C. It might result from reversing the subtraction: $6 - 19 = -13$.

Choice Choice C is incorrect because this results from dividing: $\frac{19}{6} \approx 3.17$. Division doesn't solve subtraction equations.