Match the buildings in Group I with their architectural feature in Group II.\[\begin{array}{|c|c|} \hline Group I & Group II \\ \hline \text{(P) Erechtheion, Athens} & \text{(1) Hypostyle Hall} \\ \hline \text{(Q) Temple of Karnak, near Luxor} & \text{(2) Caryatid} \\ \hline \text{(R) Hagia Sophia, Istanbul} & \text{(3) Pendentive} \\ \hline \text{(S) Pantheon, Rome} & \text{(4) Flying buttress} \\ \hline \text{(5) Oculus} \\ \hline \end{array}\]