What is the ruling on prayer and fasting for a young woman whose menstruation ceased temporarily for two months, then she saw a spot of blood for one day?

The majority of scholars hold that the minimum duration of menstruation is one day and one night. Accordingly, a single spot of blood has no ruling unless the bleeding continues for a day and a night, and ghusl (ritual bathing) and wudu' (ablution) are obligatory. Imam Malik, however, is of the view that there is no minimum limit for menstruation; thus, a single drop of blood is considered menstruation if it occurs during the possible time of menstruation (after 15 days from the previous menstrual period), necessitating ghusl and invalidating fasting. As for Imam Abu Hanifa, he believes that the minimum duration of menstruation is three days, but scholars have weakened his evidence.