Which constellation is the brightest in the night sky on the vernal equinox?

This statement is wrong. Constellation is the general term for the projection of celestial bodies and space on a celestial sphere in the sky. How can there be the brightest one? If there are only the most prominent constellations, this problem may make some people with little astronomical knowledge work.

If I had to answer the most remarkable constellation that can be observed at the vernal equinox, I would answer Orion.