Answer

It should be written as:

Gyan nu ek saadhan

Here, the letter “n” is used in Gyan and nu.

Explanation

In Gujarati meaning:

જ્ઞાનનું એક સાધન means one means/source/tool of knowledge.

So in English transliteration, you can write:

• Gyan nu ek saadhan
• or more joined: Gyannu ek saadhan

Takeaway

The correct sense is: જ્ઞાનનું એક સાધન — “a means of knowledge.”