The Warburg effect is the:

• A
  Inhibition of $C_{3}$-cycle by $O_{2}$
• B
  Inhibition of $C_{4}$-cycle by $O_{2}$
• C
  Inhibition of $C_{3}$-cycle by $CO_{2}$
• D
  Inhibition of $C_{4}$-cycle by $CO_{2}$