This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

In February 1939, he received news from his sisters that his mother was dying. On 10 February 1939, Pope Pius XI died. Roncalli was unable to see his mother for the end as the death of a pontiff meant that he would have to stay at his post until the election of a new pontiff. Unfortunately, she died on 20 February 1939, during the nine days of mourning for the late Pius XI. He was sent a letter by Cardinal Eugenio Pacelli, and Roncalli later recalled that it was probably the last letter Pacelli sent until his election as Pope Pius XII on 2 March 1939. Roncalli expressed happiness that Pacelli was elected, and, on radio, listened to the coronation of the new pontiff.
When did he hear that his mother was dying?