Option a is the correct answer. Pietra dura started in Jahangir's reign. Pietra dura is an inlay work that uses small pieces of semi-precious stones to create intricate patterns. The stones are cut into very thin slices and then arranged to create the desired pattern. The stones are held in place with a mixture of resin and glue. It was used extensively in Mughal architecture to decorate the walls of mosques, tombs, and palaces. The patterns were often floral, and they were made of semi-precious stones such as lapis lazuli, carnelian, and turquoise. Pietra dura inlay work can be found in many of the most famous Mughal buildings, including the Taj Mahal, the Red Fort, and the Jama Masjid.