ANS:C - anhydrous ammonia, air and water.

The correct combination of raw materials for nitric acid manufacture is anhydrous ammonia, air, and water. The production of nitric acid typically involves the Ostwald process, which utilizes ammonia as the primary source of nitrogen. In this process, anhydrous ammonia (NH3) is oxidized with oxygen from the air (O2) to form nitrogen oxides, primarily nitrogen monoxide (NO), which are then further oxidized to nitrogen dioxide (NO2). These nitrogen oxides then react with water (H2O) to form nitric acid (HNO3). So, the correct option is: anhydrous ammonia, air, and water.