GATE CS 1999 Q2.21 — Asymptotic Worst Case Time and Space Complexity

If $T_1 = O(1)$, give the correct matching for the following pairs:
$$\begin{array}{|ll|ll|}\hline & \text{(M) $T_n = T_{n-1} + n$} & \text{(U) $T\_n = O(n)$} \\ \hline & \text{(N) $T_n = T_{n/2} + n$} & \text{(V) $T\_n = O(n \log n)$} \\ \hline & \text{(O) $T_n = T_{n/2} + n \log n$} & \text{(W) $T\_n = O(n^2)$} \\ \hline & \text{(P) $T_n = T_{n-1} + \log n$} & \text{(X) $T\_n = O(\log^2 n)$} \\ \hline \end{array}$$