In 2002, Elizabeth marked her Golden Jubilee. Her sister and mother died in February and March respectively, and the media speculated whether the Jubilee would be a success or a failure. She again undertook an extensive tour of her realms, which began in Jamaica in February, where she called the farewell banquet "memorable" after a power cut plunged the King's House, the official residence of the governor-general, into darkness. As in 1977, there were street parties and commemorative events, and monuments were named to honour the occasion. A million people attended each day of the three-day main Jubilee celebration in London, and the enthusiasm shown by the public for the Queen was greater than many journalists had expected.
What was Elizabeth's mother's name? (If the question is unanswerable, say "unanswerable")
unanswerable