The mass of one molecule of water is approximately

• A. \[3\times {{10}^{-23}}\,g\]          
• B.         18 g
• C. \[\text{1}.\text{5 }\times \text{ 1}{{0}^{-\text{23}}}\text{ g}\]      
• D.         \[\text{4}.\text{5 }\times \text{ 1}{{0}^{-\text{23}}}\text{ g}\]