Recall that electrons found closer to our proton, to our nucleus are more stable. They're lower in energy. And that's exactly why when electrons are found in the s orbital, they're more stable than if they're found in the p orbital, because the S orbital is closer to the nucleus than the p orbital. And therefore, if we have more S character, which we have in this SP hyperbased orbital, those electrons will be more stable because they are closer to the nucleus. So once again, electrons found closer to the nucleus are more stable. Therefore, since that seed ali contains more S character 60% in the SP orbital than the methi, which contains 25% S character, acetyllide is more stable.