CORRECT OPTION IS (B).
A single pass assembler scans the program only once and creates the equivalent binary program.

Introduction:
A single pass assembler is a type of assembler that can generate machine code in a single pass over the source code. This means that it processes the source code only once, without the need for multiple passes. One of the challenges with a single pass assembler is handling forward references, which occur when a symbol is used before it is defined in the source code. In this response, we will explain how putting the code segment after the data segment can help avoid most of the forward references in a single pass assembler.

Explanation:
In a single pass assembler, the code is processed sequentially from top to bottom. When a forward reference is encountered, the assembler does not have access to the symbol's address or value because it has not been defined yet. This can lead to errors during the assembly process, as the assembler cannot resolve the reference.

However, by placing the code segment after the data segment, we can avoid most of the forward references. Here's why:

1. Data segment:
- The data segment contains declarations of variables and constants.
- These declarations do not depend on the code segment and can be processed first.
- As the assembler encounters data declarations, it can assign addresses or values to the symbols.
- By the time the assembler reaches the code segment, all the symbols in the data segment have been defined.
- This means that there are no forward references within the data segment.

2. Code segment:
- By placing the code segment after the data segment, we ensure that all the symbols in the data segment have been defined before they are used in the code segment.
- This eliminates the possibility of forward references within the code segment.
- The assembler can directly generate machine code for instructions, as it has access to the addresses or values of symbols used in the code segment.

3. Exceptions:
- It's important to note that not all forward references can be avoided by placing the code segment after the data segment.
- There may still be some cases where forward references occur, such as when a symbol is used before it is defined even within the code segment.
- However, by following this restriction, we can significantly reduce the number of forward references in a single pass assembler.

Conclusion:
Placing the code segment after the data segment in a single pass assembler helps avoid most of the forward references. This is because it allows the symbols in the data segment to be defined before they are used in the code segment, eliminating forward references within the data segment. While there may still be some exceptions, this restriction greatly simplifies the assembly process and reduces the chances of errors due to forward references.

Hahs