Option b is the correct answer. Haji Begum, the wife of the Mughal Emperor Humayun, constructed the mausoleum known as "Humayun's Tomb" in Delhi, India. The tomb was built in memory of her husband after his death in 1556. It is an iconic architectural masterpiece, is a UNESCO World Heritage Site, and it was the first garden-tomb on the Indian subcontinent that was considered a precursor to the Taj Mahal, which was built later by Emperor Shah Jahan for his wife, Mumtaz Mahal.