The balanced equation for photosynthesis is:
\[ 6H_2O + 6CO_2 \rightarrow C_6H_{12}O_6 + 6O_2 \]
This equation properly represents the molecules involved in the process of photosynthesis, where six molecules of water and six molecules of carbon dioxide are used to produce one molecule of glucose and six molecules of oxygen. Therefore, the correct response is:
\[ 6H_2O + 6CO_2 \rightarrow C_6H_{12}O_6 + 6O_2 \]