Which image srcset downloads

On a 1000px wide viewport with a device pixel ratio of 2, which file will the browser most likely choose?

<img
  srcset="hero-480.jpg 480w, hero-800.jpg 800w,
          hero-1200.jpg 1200w, hero-1600.jpg 1600w"
  sizes="(min-width: 800px) 50vw, 100vw"
  src="hero-800.jpg" alt="Abu Dhabi corniche">