The correct answer is option 1, Ustad Ahmad Lahouri. He was the architect of the Taj Mahal.

Option 2, Norman Foster, is not the correct answer. Norman Foster is a famous contemporary architect but he did not design the Taj Mahal.

Option 3, Henry Irwin, is also not the correct answer. Henry Irwin was an architect who worked in British India, but he did not design the Taj Mahal.

Option 4, Ustad Ghani Utbuddin, is not the correct answer either. There is no historical evidence or records to suggest that Ustad Ghani Utbuddin was involved in the construction of the Taj Mahal.

Therefore, the correct answer is option 1, Ustad Ahmad Lahouri. He is credited with designing and overseeing the construction of the Taj Mahal.