Seed formation without fertilisation in flowering plants involves the process of
Apomixis
Apomixis is an asexual reproduction that forms seeds without fertilisation and produces a maternal clone in plants.
The embryo develops from diploid cells of the nucellus, integument, diploid egg or some other gametophytic cell.
It is observed in plants of the family Rosaceae, Asteraceae, Poaceae etc.
Final answer
b. Apomixis.