Given below are two statements.
Statement $I:$ In polluted water,values of both dissolved oxygen and $BOD$ are very low.
Statement $II:$ Eutrophication results in a decrease in the amount of dissolved oxygen.
In the light of the above statements,choose the most appropriate answer from the options given below.

• A
  Both Statement $I$ and Statement $II$ are true
• B
  Both Statement $I$ and Statement $II$ are false
• C
  Statement $I$ is true but Statement $II$ is false
• D
  Statement $I$ is false but Statement $II$ is true