The correct answer is B. Winter solstice.
The winter solstice is the day with the fewest hours of daylight in the Northern Hemisphere. It occurs on December 21 or 22 each year. On this day, the Northern Hemisphere is tilted away from the sun, and the sun appears to be at its lowest point in the sky. This means that the days are shorter and the nights are longer.
The summer solstice is the day with the most hours of daylight in the Northern Hemisphere. It occurs on June 20 or 21 each year. On this day, the Northern Hemisphere is tilted towards the sun, and the sun appears to be at its highest point in the sky. This means that the days are longer and the nights are shorter.
The vernal equinox is the day when the sun crosses the equator from south to north. It occurs on March 20 or 21 each year. On this day, the length of day and night are equal in both the Northern and Southern Hemispheres.
The autumnal equinox is the day when the sun crosses the equator from north to south. It occurs on September 22 or 23 each year. On this day, the length of day and night are equal in both the Northern and Southern Hemispheres.