In figure coefficient of friction between m₁ and m₂ is μ and that between m₁ and the wall is zero. A force F is pressing the system against the wall. Minimum value of force required to hold the system in equilibrium if coefficient of friction between m₁ and the wall is μ, and, f₁ and f₂ are, respectively, the force of friction on m₁ and m₂,then:

• A

  f₁ and f₂ both are downward

• B

  f₁ and f₂ both are upward

• C

  f₁ is upward and f₂ downward

• D

  f₁ is downward and f₂ upward