Correct Answer: Expands

Solution : The correct option is the fourth option.

Contracts refer to the action of becoming smaller or reducing in size or volume. On the other hand, "expands " signifies the opposite action, indicating growth or an increase in size or volume. When air is blown into a balloon, it expands or gets larger as it fills with air. Hence, contracts and expands are antonyms in this context.

The meanings of the other options are as follows:

• Control means to manage, direct, or influence something.
• Repulses means to drive back or repel something.
• Shrinks also mean to become smaller in size or reduce in dimensions, similar to "contracts".

Therefore, the correct answer is expands.