The Subsidiary Alliance System was a policy implemented by the British during their colonial rule in India. It aimed to ensure control and dominance over the Indian states.

Option 1 states that a subsidiary British army was to be maintained in the Indian State. This was indeed a feature of the Subsidiary Alliance System. The British would station their own troops within the state to maintain control and protect their interests.

Option 2, which is the correct answer, states that the determination of expenses incurred on the subsidiary British army was the duty of the Indian State. However, this is not a feature of the Subsidiary Alliance System. In fact, it was the responsibility of the British East India Company to bear the expenses of maintaining the subsidiary army.

Option 3 states that the Indian State had to keep a British resident in her capital. This was also a feature of the Subsidiary Alliance System. The British resident would act as a representative of the British government and ensure compliance with their policies.

Option 4 states that Indian soldiers could be used by the Company commanders. This was another feature of the Subsidiary Alliance System. The British would take advantage of the Indian military resources to further their own goals.

In conclusion, option