The correct option is A True
This rule gives an average year length of 365.25 days. So, if we add a quater of a day of 4 years we will get one full day .This day is added to the fourth year in the month of February , usually has 28 days but during the leap year there is an addition of 29th day in the calendar . Hence , leap year occurs once in every 4 years. Hence, the statement is true.