Answer:
e.iv, iii, i, ii
Explanation:
Be has electron configuration of 1s^2 2s^2. During bond formation, one 2s electron is promoted to a 2p orbital. Hence two hybrid sp beryllium orbitals are formed. These two hybrid orbitals are used in sigma bond formation to fluorine atoms.
Recall that fluorine has filled 2p orbitals containing lone pairs of electrons. These filled orbitals can interact with the unhybridized 2p-orbitals on beryllium to form pi bonds. This is the reason for the sequence of events chosen in the answer.