One of these religious events occurs in the month of Sivan, and commemorates the success of the wheat harvest and the day in which the holy book of that namesake faith was presented on Mount Sinai. Another one of these events occurs in March, and commemorates the failure of Haman to massacre members of the namesake faith as described in the Book of Esther. For 10 points, name these events of the namesake faith group, examples of which include Shavuot, Purim, and Hanukkah.
a) Ramadan
b) Diwali
c) Rosh Hashanah
d) Yom Kippur