Answer - D.
Dynamic RAM requires periodic recharging.
Dynamic RAM functions like a capacitor. It gradually discharges. This method requires that it be updated sometimes to recharge a bit value of 1 before it becomes too low to be recognized. The refresh process or recharging will do many memory cell accesses at once to be effective; otherwise, it would never be able to keep up and would also interfere with regular operation.
The detailed solution to the question of which memory requires periodic recharging is provided here.
Because it takes time to access those cells, DRAM is slower. Unlike static RAM, which has a slightly different organizational structure and is quicker to reach the expense of consuming more power.
DRAM is less expensive because it uses both capacitors and transistors but must sometimes refresh to maintain its 1s and 0s as such.
The RAM is corrupted if the voltage crosses a specific level range since it cannot distinguish between 1 and 0.
Hence, Option (D) is the correct answer.