When is Easter Sunday celebrated?

Easter Sunday is celebrated on the first Sunday following the first full moon after the vernal equinox (approximately March 21). This method of determining the date of Easter is rooted in the Christian tradition and is linked to the timing of Passover in the Jewish calendar, as the events of Easter are connected to those of Passover. The Church of Alexandria's calculations established this formula to maintain a consistent liturgical celebration, ensuring that Easter always falls in the spring.

The other dates mentioned do not align with this established understanding of Easter. The first Sunday of March, the last Sunday of April, and the second Sunday of May do not reflect the astronomical events that the date of Easter is based upon, which is why they are not correct answers. The formula in option B remains the widely accepted method used by many Christian denominations to determine the date of Easter each year.