The neoclassical zone sits at the far right of the SRAS curve, where it is nearly vertical and output is at or near potential GDP. In this zone, what does a shift in AD mainly affect, and what is the only way to raise real GDP further?

1. In the neoclassical zone, the SRAS curve is nearly vertical, since inputs are already fully employed. 2. A shift in AD along a near-vertical SRAS mostly moves the intersection vertically, changing the price level a great deal. 3. Because the SRAS curve barely runs sideways here, output barely moves in response to the same AD shift. 4. Since AD shifts cannot pull much more output out of an economy already near capacity, only a rightward shift of AS itself can raise real GDP further. 5. Option D wrongly claims AD can still raise GDP here, which contradicts this near-vertical relationship. _Source: OpenStax Principles of Macroeconomics for AP Courses (CC BY 4.0), Ch 10 "The Aggregate Demand/Aggregate Supply Model", section 10.6 | Keynes’ Law and Say’s Law in the AD/AS Model_