A filesystem is the methods and data structures that an operating system uses to keep track of files on a disk or partition; that is, the way the files are organized on the disk.
A thread is a path of execution within a process within the CPU.
Th virtual address space is the memory that an individual program sees when it executes.
An interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention.
$\begin{array}{|c|c|c|c|} \hline {}& \text{List-I} & {} & \text{List-II} \\ \hline (a) & \text{Disk} & (iii) & \text{File System} \\ \hline (b) & \text{CPU} & (i) & \text{Thread} \\ \hline (c) & \text{Memory} & (iv) & \text{Virtual address space} \\ \hline (d) & \text{Interrupt} & (ii) & \text{Signal} \\ \hline \end{array}$
$\therefore$ Option $B.$ is the correct answer.