The 'Blue Moon' phenomenon occurs

Correct option is A

Correct Answer:A. When two full moons occur in the same month.

• The phenomenon of a "Blue Moon" occurs when there are two full moons in a single calendar month. This happens because the lunar cycle (from one full moon to the next) is about 29.5 days, which is shorter than most months (which have either 30 or 31 days).

• The term "Blue Moon" doesn't actually refer to the moon’s color but simply signifies the rarity of the event, as normally there is only one full moon per month.

• Blue Moon can also be used to describe an extra full moon in a season, which can occur when there are four full moons in a single season. However, the more commonly referenced definition is when two full moons appear in the same month.

• The expression “once in a blue moon” has become synonymous with something that happens very rarely.