An insulated system contains $4$ moles of an ideal diatomic gas at temperature $T$. When a heat $Q$ is supplied to the gas,$2$ moles of the gas is dissociated into atoms and the temperature remains constant. Then the relation between $Q$ and $T$ is ($R=$ universal gas constant.)

• A
  $Q=R T$
• B
  $Q=2 R T$
• C
  $Q=3 R T$
• D
  $Q=4 R T$