Given below are two statements:
Statement $I$: The relationship between $HbO_2$ saturation and oxygen tension $(pO_2)$ is called the oxygen-dissociation curve.
Statement $II$: The oxygen dissociation curve shifts towards the right due to a decrease in $ppCO_2$ and a decrease in temperature.
In the light of the above statements,choose the most appropriate answer from the options given below.

• A
  Statement $I$ is correct but Statement $II$ is incorrect.
• B
  Statement $I$ is incorrect but Statement $II$ is correct.
• C
  Both Statement $I$ and Statement $II$ are correct.
• D
  Both Statement $I$ and Statement $II$ are incorrect.