For the line y = 2x + b, if the value of b increases by 4, how does the line's x-intercept change?

Find the $x$-intercept by setting $y = 0$: $0 = 2x + b$, so $x = -\frac{b}{2}$. When $b$ increases by 4, the new intercept is $-\frac{b+4}{2} = -\frac{b}{2} - 2$. The intercept decreases by 2, choice B. Geometrically, raising the line by 4 units with slope 2 means the line reaches the $x$-axis 2 units sooner when moving left. Choice A (increases by 4) confuses the $x$-intercept with the $y$-intercept. Choice C (increases by 2) gets the right size but the wrong direction. Choice D (stays the same) ignores that the intercept depends on $b$.