The Indian Council Act of 1861 is the correct answer. This Act strengthened the Viceroy’s authority over his executive council by substituting the “portfolio” or departmental system for corporate functioning.

Option 2 references the Government of India Act, 1858. This is not the correct answer. This Act was introduced not to change the departmental system but to transfer the power to rule from the East India Company to the British Crown following the 1857 rebellion.

Option 3, the Indian Councils Act of 1892, increased the number of additional (non-official) members in the Central and provincial legislative councils, but did not strengthen the Viceroy’s executive control.

Finally, option 4, the Indian Councils Act of 1909, also known as the Morley-Minto Reforms, expanded the Indian council but did not substitute the departmental system for corporate functioning.

Therefore, the Indian Council Act, 1861 - option 1 is the correct answer.