The graph showing the concept of activation energy of an enzyme is given below. Observe the graph and choose the correct option for $M$ and $N$.

• A
  $M$-High temperature,High activation energy,$N$-Low temperature,Low activation energy
• B
  $M$-High substrate,High activation energy,$N$-Low substrate,Low activation energy
• C
  $M$-Activation energy without enzyme,$N$-Activation energy with enzyme
• D
  $M$-Activation energy with enzyme,$N$-Activation energy without enzyme