In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.

Passage: The second largest February tornado outbreak on record impacted the Gulf Coast and East Coast regions of the United States beginning on February 23. The first significant tornadoes of the outbreak moved across southeastern Louisiana and southern Mississippi that evening, leaving significant damage and three deaths. The towns of Livingston and Laplace, Louisiana sustained heavy damage from strong EF2 tornadoes, and another EF2 near Purvis, Mississippi killed one person in a mobile home. An EF3 tornado also caused major structural damage in Paincourtville, Louisiana before destroying an RV park in Convent, killing two people at that location. Three simultaneous waterspouts were observed over Lake Pontchartrain during the event as well. Later that night, a large supercell thunderstorm developed over the Gulf of Mexico and moved ashore, producing a destructive EF3 tornado in Pensacola, Florida. The tornado injured three people and destroyed homes, townhouses, apartments, and a GE warehouse.
 Link Information: Lake Pontchartrain ( ; , ) is a brackish estuary located in southeastern Louisiana in the United States. It covers an area of 630 sqmi Answer: 17563392000
What is the square footage of the lake over which three simultaneous waterspouts were observed during the tornado outbreak that began on February 23rd?

Passage: He began his career at Rangers, where he made 2 appearances. Walker made his senior league début in a 1–0 win over Motherwell at Fir Park, coming off the bench to replace Hamed Namouchi. Walker had a six-month loan spell at Clyde in which he made his Bully Wee début in a 1–0 victory at Broadwood Stadium against Ross County. During this time, Walker won the SFL young player of the month award for September 2004. After his short-term deal at Broadwood, Walker went to Sweden for a couple of months but decided to come back home. he joined Morton in July 2005. Walker made his Morton début in a 3–2 (AET) Challenge Cup win over Gretna, in which assistant boss at Morton, Derek Collins, and later-to-be teammate Ryan McGuffie played for the opposition. His senior league debut was the following week against Raith Rovers, in which Morton triumphed 2–0 in front of 3,222 fans. He signed a new contract in May 2009, for another year at Morton. Being out of contract in the summer, and struggling for fitness, Walker was loaned to Brechin City for three months in January 2010. Walker suffered a recurrence of a groin injury, where he underwent surgery but remained at Brechin until April. He was released at the end of the 2009–10 season. After his release from Morton, Walker decided to go part-time and was signed up by ex-manager Jim McInally at East Stirlingshire for the 2010–11 season.
 Link Information: none Answer: none
How many goals did Ryan McGuffie have for Gretna?

Passage: German Type IXD2 submarines were considerably larger than the original Type IXs. U-861 had a displacement of when at the surface and while submerged. The U-boat had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines plus two MWM RS34.5S six-cylinder four-stroke diesel engines for cruising, producing a total of for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to .
 Link Information: The range was extended to 31,500 nmi Answer: 7800

How much larger were the improved German submarines?