How much flux from the Sun does the Northern Hemisphere of Earth receive compared to the Southern Hemisphere on the first day of fall at noon

Both the hemispheres would receive equal flux from the sun at noon on the first day of fall.

Explanation:

In the Northern hemisphere, the first day of fall marks the autumnal/fall/September equinox while the same day in the Southern hemisphere denotes the beginning of spring in March. 'Autumnal equinox' is characterized as the moment when the sun appears to cross the celestial equator while tilting away from the observer. This is why the flux of the sun received by the two hemispheres on equinox remains the same and they both are equally lit by the sun's light as the night and day on this day are divided equally.

a. i. only is correct.