The Congress ministries resigned in the seven provinces in 1939, because

The correct answer is D because the primary reason for the resignation of the Congress ministries in 1939 was the unilateral decision of the British government to involve India in World War II.

The Viceroy, Lord Linlithgow, declared India a party to the war against Germany without consulting the Indian National Congress or the provincial legislatures. The Congress demanded that the British government state its war aims and guarantee immediate self government or independence after the war as a condition for cooperation. When the British government failed to provide a satisfactory response, the Congress Working Committee ordered the provincial ministries to resign in protest.

Since none of the options A, B, or C mention the British involvement of India in the war without consent, they are all incorrect.