Question: Lee Valley White Water Centre was officially opened by the only daughter of what Queen?

Context paragraphs:
Anne, Princess Royal: Anne, Princess Royal, {'1': ", '2': ", '3': ", '4': "} (Anne Elizabeth Alice Louise; born 15 August 1950) is the second child and only daughter of Queen Elizabeth II and Prince Philip, Duke of Edinburgh.  At the time of her birth, she was third in the line of succession to the British throne, behind her mother – then Princess Elizabeth – and elder brother, Charles.  She rose to second after her mother's accession, but is currently 12th in line.

Lee Valley Leisure Complex: Lee Valley Leisure Complex is located at Edmonton, London, and is part of the Lee Valley Park.  It was formerly known as the Picketts Lock Sports Centre.  It now comprises an 18-hole golf course which borders the River Lee Navigation, camping site, indoor bowls club (housed in the remains of the now-demolished Picketts Lock Sports Centre), multiplex cinema and restaurants.  A new athletics centre was formally opened on 16 January 2007.  The complex is owned and managed by the Lee Valley Regional Park Authority (LVRPA).

Lee Valley Athletics Centre: The Lee Valley Athletics Centre is located at the Lee Valley Leisure Complex formerly known as Picketts Lock in Edmonton, London Borough of Enfield.  The centre cost £15m to build, and was officially opened on 16 January 2007 by Minister for the Olympics, Tessa Jowell.  The centre is owned and managed by the Lee Valley Regional Park Authority (LVRPA)

Canoeing at the 2012 Summer Olympics: The canoeing races at the 2012 Olympic Games in London were contested in two main disciplines: the slalom, from 29 July to 2 August, and the sprint, from 6 to 11 August.  The slalom competition was held at the Lee Valley White Water Centre and the sprint events were staged at Eton College Rowing Centre, at Dorney Lake, known as Eton Dorney.

White Water Bay (Oklahoma): White Water Bay is a water theme park in Oklahoma City, Oklahoma built in 1981.  Built by the Herschend Family Entertainment Corporation and originally known as White Water, the water park was picked up by Premier Parks (then known as Tierco) in 1991 and its name was changed to "White Water Bay".  Both White Water Bay and the nearby theme park Frontier City were sold again in a seven park package by Six Flags on January 11, 2007, for $312 million.  White Water Bay is currently owned by EPR Properties and operated by Premier Parks, LLC.

Lee Valley White Water Centre: Lee Valley White Water Centre (previously known as Broxbourne White Water Canoe Centre) is a white-water slalom centre, that was constructed to host the canoe slalom events of the London 2012 Olympic Games.  On 9 December 2010, Anne, Princess Royal officially opened the venue which is owned and managed by Lee Valley Regional Park Authority.  The £31 million ($50 million US) project to construct the centre finished on schedule and was the first newly constructed Olympic venue to be completed.

London Canoe Slalom Invitational: The London Canoe Slalom Invitational was an international Canoe Slalom event held at the Lee Valley White Water Centre between July 28 and 31 2011.  The Regatta was closed to the media and public.  It was a 2012 Olympics test event and was part of the London Prepares series

RapidBlocs: RapidBlocs are a moveable obstacle system.  The system was developed by Scott Shipley of S2o Design and Engineering and Andy Laird of Engineering Paddler Design.  The system was developed for the Lee Valley White Water Centre that was used for the 2012 London Olympic Games.  The system is made of modular blocs, among other shapes, that can be secured via unistrut at any point in a compatible channel.  The blocs are stackable and can therefore be combined to create a variety of shapes.  These shapes are configured to create waves, eddies, other hydraulic jumps.  There are also a variety of utilitarian configurations that can be created to make stairs, rescue platforms, and to configure varying rescue scenarios for rescue training.  At the London Games the RapidBloc system created all of the waves and features and was also used to create the starting gate.

2015 ICF Canoe Slalom World Championships: The 2015 ICF Canoe Slalom World Championships were the 37th edition of the ICF Canoe Slalom World Championships.  The event took place from 15 to 20 September 2015 in London, United Kingdom, under the auspices of International Canoe Federation (ICF), at the Lee Valley White Water Centre facility, which was also the venue for the canoe slalom events at the 2012 Summer Olympics.

Canolfan Tryweryn: Canolfan Tryweryn (grid reference [ SH890401] ) is the National White Water Centre for Wales, and is based near Bala in North Wales.  It developed the first commercial white water rafting operation in the UK in 1986, and since then has grown to become the largest and most well-respected rafting organisation in the UK.  The centre is home to paddlesport National Governing Body Canoe Wales.  The National White Water Centre is ideal for canoeing, kayaking, play-boating and coached groups who sometimes run BCU/CW Star Awards.

Supporting paragraphs: Lee Valley White Water Centre Anne, Princess Royal
Answer: Queen Elizabeth II