When the southern hemisphere is having its fall equinox, what's happening in the northern hemisphere?

The September equinox occurs the moment the Sun crosses the celestial equator – the imaginary line in the sky above the Earth's Equator – from north to south. This happens either on September 22, 23, or 24 every year

B

Explanation:

When the South has its fall, the North has its spring

answer; (d) melting of sea ice;