The correct answer is option 4: 1, 2, and 4.

To understand why this is the correct answer, let`s analyze each option given in the question:

Option 1: Indian Railways - This option refers to the Indian Railways as a landmark of Dalhousie`s administration. However, there is no evidence to suggest that Indian Railways was a landmark of Dalhousie`s administration, so this option is incorrect.

Option 2: 1, 3, and 4 - This option includes Indian Railways, English as the medium of instruction, and the Telegraph as landmarks of Dalhousie`s administration. As we discussed earlier, Indian Railways is not a valid landmark. Although English as the medium of instruction was introduced during Dalhousie`s administration, there is no specific mention of it being a landmark. The Telegraph, on the other hand, was indeed introduced by Dalhousie, making it a valid landmark. Therefore, this option is not entirely correct.

Option 3: 2, 3, and 4 - This option includes the Public Works Department, English as the medium of instruction, and the Telegraph as landmarks of Dalhousie`s administration. As we mentioned earlier,