30 nano seconds

30 micro seconds

30 pico seconds

0.3 seconds

To perform address translation to reduce size of the memory

To perform address translation to reduce execution time overhead

Both 1) To perform address translation to reduce size of the memory and 2) To perform address translation to reduce execution time overhead

None of the above

By the CPU that contains a special refresh counter, only

By an external refresh controller, only

Either by the CPU or by an external refresh controller

None of these

Magnetic core memory

Semiconductor memory

Thin film memory

None of these

6 transistors

2 transistors and 2 capacitors

1 transistor and 1 capacitor

None of these