The correct option is A Casuarina
When the fertilisation is preceded by the entry of the pollen tube from the chalazal end of the embryo sac, then it is called chalazogamy. Chalazogamy is seen in Casuarina.
In Lily, porogamy is seen i.e. the entry of the pollen tube from the micropylar end.
In Cucurbita, mesogamy is seen i.e. the entry of the pollen tube from the integuments.