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.

On November 30, 2010, CBC's senior director of regulatory affairs issued a letter to the CRTC regarding CBC's plans for transitioning to digital. The letter states, "CBC/Radio-Canada will not be converting its analogue retransmitters in mandatory markets to digital after August 31, 2011."  On December 16, 2010, some months after the CRTC issued a bulletin reminding broadcasters that analog transmitters had to be shut off by the deadline in mandatory markets, the CBC revised the documents accompanying its August 6, 2010 news release to state that it had the money for and is striving to transition all 27 transmitters by August 31, 2011.
On which day did CBC release an updated announcement stating they were striving to update all 27 transmitters?

In the early 19th century, the Indigenous American woman Sacagawea, who would help translate for and guide the Lewis and Clark Expedition in the West, married the French trapper Toussaint Charbonneau. Most marriages between Europeans and Indigenous Americans were between European men and Indigenous American women. Depending on the kinship system of the woman's tribe, their children would be more or less easily assimilated into the tribe. Nations that had matrilineal systems, such as the Creek and Cherokee in the Southeast, gave the mixed-race children status in their mother's clans and tribes. If the tribe had a patrilineal system, like the Omaha, the children of white fathers were considered white. Unless they were specifically adopted into the tribe by an adult male, they could have no social status in it.
Who married Sacagewea?

While Japan had a large number of submarines, they did not make a significant impact on the war. In 1942, the Japanese fleet subs performed well, knocking out or damaging many Allied warships. However, Imperial Japanese Navy (and pre-war U.S.) doctrine stipulated that only fleet battles, not guerre de course (commerce raiding) could win naval campaigns. So, while the US had an unusually long supply line between its west coast and frontline areas, leaving it vulnerable to submarine attack, Japan used its submarines primarily for long-range reconnaissance and only occasionally attacked U.S. supply lines. The Japanese submarine offensive against Australia in 1942 and 1943 also achieved little.

What doctrine stated that only fleet battles could win naval campaigns?