Select the correct option for $\beta$-galactosidase.

• A
  $H_2O + \text{Lactose} \rightarrow \text{Glucose} + \text{Galactose}$
• B
  $H_2O + \text{Galactose} \rightarrow \text{Glucose} + \text{Lactose}$
• C
  $H_2O + \text{Lactose} \rightarrow \text{Galactose} + \text{Maltose}$
• D
  $H_2O + \text{Maltose} \rightarrow \text{Glucose} + \text{Glucose}$