The correct answer is option 3 - Srinagar. In Srinagar, there is a Muslim mosque where a hair of Prophet Mohammad Saheb has been preserved. It is important to note that the hair is considered to be a sacred relic in Islamic tradition. While options 1, 2, and 4 are incorrect, here is some additional information about them:

1) Ajmer is home to the famous Ajmer Sharif Dargah, which is the mausoleum of Sufi saint Khwaja Moinuddin Chishti.

2) Ahmedabad has several historical mosques, but none of them are known for preserving any relics of Prophet Mohammad Saheb.

4) Mecca is the holiest city in Islam, housing the Kaaba, but there is no specific mosque mentioned as the location for preserving the hair of Prophet Mohammad Saheb.