Answer
Diagram "B" shows the final volume of the balloon for that situation.
Work Step by Step
At constant pressure, if the Kelvin temperature doubles, the volume of the balloon will also double its value. (Charles's Law).
But, at the same time, if we remove one half of the gas atoms, the volume will also be halved. (Avogadro's Law)
If the volume is doubled by the temperature raise, and halved by the gas leak, it stays the same at the end. Therefore, diagram "B" is the best representation for that.
