Arrange the following structures from largest to smallest, assuming that they belong to two generations of the same angiosperm.

1. ovary
2. ovule
3. egg
4. carpel
5. embryo sac

a. 4, 2, 1, 5, 3

b. 5, 4, 3, 1, 2

c. 5, 1, 4, 2, 3

d. 4, 1, 2, 5, 3