State whether the following statements are True or False:
$I.$ The total organic matter synthesized by the producers in the process of photosynthesis per unit time and area is known as gross primary productivity.
$II.$ Net primary productivity is the weight of the organic matter stored by the producers in a unit area/volume per unit time.

• A
  $I$ is true while $II$ is false.
• B
  $II$ is true while $I$ is false.
• C
  $I$ and $II$ are true.
• D
  $I$ and $II$ are false.