Given below are two statements :

Statement $I$ : If $BOD$ is $4\,ppm$ and dissolved oxygen is $8\,ppm$, then it is a good quality water.

Statement $II$ : If the concentration of zinc and nitrate salts are $5 ppm$ each, then it can be a good quality water.

In the light of the above statements, choose the most appropriate answer from the options given below :

• A

  Both the statements $I$ and $II$ are incorrect

• B

  Statement $I$ is incorrect but Statement $II$ is correct

• C

  Both the statements $I$ and $II$ are correct

• D

  Statement $I$ is correct but Statement $II$ is incorrect