Option 1: 0.3 m/s

This option suggests that the recoil velocity of the pistol is 0.3 m/s. However, this is incorrect because the recoil velocity is expected to be negative. When the bullet is fired in one direction, the pistol experiences an equal and opposite force in the opposite direction, resulting in a negative recoil velocity.

Option 2: 3 m/s

This option states that the recoil velocity of the pistol is 3 m/s. This is incorrect because, according to the principle of conservation of momentum, the momentum before the firing and after should be equal in magnitude but opposite in direction. Therefore, the recoil velocity should have the same magnitude as the bullet`s velocity but in the opposite direction, which in this case, is -300 m/s.

Option 3: -3 m/s

This option correctly states that the recoil velocity of the pistol is -3 m/s. As mentioned earlier, the recoil velocity has the same magnitude as the bullet`s velocity but opposite in direction. Therefore, the correct answer is option 3.

Option 4: -0.3 m/s

This option suggests that the recoil velocity of the pistol is -0.3 m/s. However, since the bullet is fired with a