Introduction:
The Harappan civilization, also known as the Indus Valley civilization, thrived in the Indus River Valley around 2600-1900 BCE. One of the intriguing aspects of this ancient civilization is their writing system, known as the Harappan script. While much is still unknown about this script, several features have been identified. In this context, we will discuss the features of Harappan writing and identify the one that does not belong.

Features of Harappan Writing:
1. Pictographic and not alphabetical: The Harappan script is believed to be a pictographic script, where symbols or signs represent objects, concepts, or sounds. These signs are not based on an alphabetical system like the modern English alphabet. Instead, they are pictorial representations that convey meaning.

2. Not deciphered by James Prinsep: The Harappan script has not been deciphered or fully understood yet. While several attempts have been made to decipher it, no consensus has been reached. James Prinsep was an English scholar who made significant contributions to the decipherment of the ancient Brahmi script, but he did not decipher the Harappan script.

3. Many signs: The Harappan script is known for its large number of signs. Estimates range from 375 to 400 signs, making it a complex writing system. However, the exact number and meaning of these signs remain uncertain due to the lack of a complete decipherment.

4. Right to left writing: The Harappan script was typically written from right to left, similar to other ancient scripts like Sumerian cuneiform and ancient Egyptian hieroglyphs. This directionality is opposite to modern scripts like English, which are written from left to right.

The Correct Answer:
The correct answer is option 'B' - "It has been deciphered by James Prinsep." This feature does not belong to the Harappan writing system. As mentioned earlier, the Harappan script has not been deciphered or fully understood yet. While several scholars have made significant contributions to its study, including James Prinsep's work on other ancient scripts, the Harappan script remains undeciphered.

Conclusion:
The Harappan script, with its pictographic nature, numerous signs, and right to left writing direction, presents a fascinating mystery for archaeologists and linguists. Despite ongoing efforts, the script's full decipherment remains elusive. It is a testament to the complexity and uniqueness of the ancient Indus Valley civilization.