In the design of a control unit of a processor, two common approaches are used: hardware control and microprogrammed control. Consider the following statements:
I. Hardware control units are generally faster but more difficult to modify than microprogrammed control units.
II. In a horizontal microprogrammed control unit, each control signal has a separate bit in the control word.
III. Vertical microprogramming leads to longer control words but provides greater parallelism.
IV. Microprogrammed control units are typically easier to implement and modify than hardware control units.
Match all items in Group 1 with correct options from those given in Group 2:
\[ \begin{array}{|c|c|} \hline \textbf{Group 1} & \textbf{Group 2} \\ \hline P. \text{ Intermediate representation} & 1. \text{ Activation records} \\ \hline Q. \text{ Top-down parsing} & 2. \text{ Code generation} \\ \hline R. \text{ Runtime environments} & 3. \text{ Leftmost derivation} \\ \hline S. \text{ Register Allocation} & 4. \text{ Graph colouring} \\ \hline \end{array} \]