Final answer:
On the day of the vernal equinox, the length of daylight is nearly equal to 12 hours due to the tilt of the Earth's axis. In Boston, the vernal equinox occurs on either day 93 or day 94. Therefore, the correct answer is b. Day 93.
Step-by-step explanation:
The length of daylight on a specific day of the year is determined by the position of the Earth in its orbit around the sun and the tilt of its axis. On the day of the vernal equinox, which occurs around March 20th, the Earth's axis is tilted neither towards nor away from the sun, resulting in nearly equal day and night lengths.
In Boston, the vernal equinox occurs on either day 93 or day 94, depending on the year. Therefore, the correct answer is b. Day 93.
It's important to note that the precise hours of daylight may vary slightly due to other factors such as atmospheric refraction and the observer's location.