在 0racle 中，下列( )语句定义了一个游标。(选择一项)
CURSCR cur For SELFCT* FROM cd
WHERE category=’ROCK’
CREATECURSOR cur FOR SELECT * FR0M cd
WHERE category=’ROCK’
CURSCR cur IS SELECT* FROM cd
WHERE category=’ROCK’
CREATE CRSOR cur IS SELECT* FROM cd
WHERE category=’ROCK’
