In computer memory hierarchy, Random Access Memory (RAM) is often described as short term or temporary memory. Which of the following properties of RAM best explains why it is used as short term memory in a computer system?

Introduction / Context:
This question examines your understanding of why Random Access Memory, commonly called RAM, is known as short term memory in computer systems. RAM plays a critical role in storing data and instructions that the processor needs immediately, but it does not hold information permanently. The term short term does not mainly refer to cost or capacity; it refers to how long the data remains valid. Understanding the volatile nature of RAM and how it fits into the broader memory hierarchy is essential for grasping the basic architecture of a computer.

Given Data / Assumptions:
The question states that RAM is used as short memory and asks which property justifies this description. The options mention cost, volatility, capacity, and programmability. We assume the system is a standard digital computer where RAM stores data while the machine is powered on and is cleared when the power is turned off. We also assume that long term storage is handled by non volatile devices such as hard disks, solid state drives, or optical media.

Concept / Approach:
RAM is volatile memory, which means that its contents are lost when the power supply is removed. This property is the main reason why RAM is used for temporary or short term storage of data and programs during active processing. While RAM is relatively fast compared to secondary storage, its data does not persist across power cycles, so it cannot be used for permanent storage. Other types of memory, such as ROM, flash memory, and disks, are non volatile and retain data without power. Therefore, when we talk about RAM as short term memory, we are emphasizing its volatility and temporary nature rather than its price or size.

Step-by-Step Solution:
Step 1: Recall that RAM stores operating system data, running programs, and active files only while the computer is powered on.Step 2: Understand that when you shut down the computer, all unsaved information in RAM is lost, which shows that it is not permanent.Step 3: Connect this behavior to the definition of volatile memory, which loses its contents when power is removed.Step 4: Conclude that RAM is called short term memory precisely because it is volatile and temporary.

Verification / Alternative check:
Consider what happens when there is a sudden power failure. Any unsaved work stored only in RAM disappears, and the system has to reload programs and data from non volatile storage when it starts again. This is direct evidence of volatility. By contrast, files stored on a hard disk or solid state drive remain intact after power loss. Documentation and textbooks also define RAM as volatile memory and distinguish it from long term memory like disk storage. This confirms that volatility is the key reason RAM is considered short term.

Why Other Options Are Wrong:
Option A is wrong because although RAM may be more expensive per unit of storage than disk storage, cost alone does not explain its role as short term memory. Option C is wrong because modern systems often have large RAM capacities, and small size is not the defining feature. Option D is wrong because programmability refers to how data is written, not to how long data persists. Only option B correctly identifies volatility as the property that makes RAM a short term storage medium.

Common Pitfalls:
Some learners mistakenly think that short term memory means physically small size or higher price, and they ignore the relationship between memory and power. Another pitfall is to confuse RAM with cache or registers, which are also temporary but exist at different levels of the memory hierarchy. Additionally, people sometimes think RAM can be used for permanent storage if enough capacity is available, which is incorrect because the data disappears when power is removed. Always link the term short term to volatility and the need for continuous power to retain data.

Final Answer:
The correct answer is It is volatile and loses its stored data when power is switched off.