Which of the following is/are advantage of virtual memory?

The overlay tree for a program is as shown below:

What will be the size of the partition (in physical memory) required to load (and run) this program?

If an instruction takes $${\rm I}$$ microseconds and a page fault takes an additional $$j$$ microseconds, the effective instruction time if on the average a page fault occurs every $$k$$ instruction is:

A $$1000$$ Kbyte memory is managed using variable partitions but to compaction. It currently has two partitions of sizes $$200$$ Kbytes and $$260$$ Kbytes respectively. The smallest allocation request in Kbytes that could be denied is for